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Generac engine test data on my FS II
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Jimmy Young

Joined: 24 Nov 2007
Posts: 182
Location: Missouri City, TX

Posted: Tue Jul 15, 2008 3:08 pm Post subject: Generac engine test data on my FS II

Hi to all,



Last Memorial Day weekend I had an engine failure on my Rotax 503.  

landed off-field with no problems other than a change of underwear. My  

503 had 205 hrs. on it when it failed. I had been contemplating  

getting a 4 stroke engine when my 300 hr. rebuild came due, so this  

just sped up the process. I was considering the HKS 700 and the  

Generac V-twin from Valley Engineering. The cost difference was  

substantial, so much so that I figured I would rather spend a little  

more and get a Mark III than get the HKS. I decided to further  

investigate the Generac.



I contacted Dick Stark in Kansas City, who owns a Kolb Mark II with  

the Generac engine. He let me come up to see the engine & hear it run,  

and would have flown it but the weather was bad. It sounded and felt  

great. He and his wife Sharon, who usually flies the Kolb, were very  

happy with it, so I drove to Valley Engineering in Rolla MO to see  

more. I was impressed with the operation and the people who own it,  

Gene and Larry Smith. They had done the install on Dick's plane, and I  

decided to order one.



The week of June 16th I trailered my plane to Rolla and they started  

the install. There are mods that were done to the engine mount area  

that required welding some 4130 angle and plate steel. The engine is  

installed direct to the frame with no shock mounts. This is done to  

control the "torsional resonance" a V-type engine can produce,  

according to Gene Smith. I'm no expert in any of that, and don't  

profess to be. I leave that up to people like the Smiths who do it  

professionally on a daily basis. I do know that I feel no more  

vibration in my plane now than when it had the 503. By Wednesday  

morning we were doing test flights at Vichey Field, also known as  

Rolla National Airport. We tried 3 different props and redrive ratios,  

and I went with the IVO 3 blade 72" with a 2.0 redrive. I headed home  

with my new engine ready to start running it through a testing period.  

The following information contains all of the performance data I have  

compiled over the last 3 1/2 weeks and the first 34 hrs. of flight  

with the new engine:



Flight Test Notes on a new Generac V-Twin engine from Valley  

Engineering, Rolla, MO.

Reduction Drive: 2.0, belt driven

Prop: IVO 72” 3 blade

HP: 40 at 3600 rpm

single Weber carb with accelerator pump, no choke or primer.

This engine is replacing a Rotax 503 DCDI.

My FS II weighs 435 lbs empty, no fuel.

For more engine information, see www.culverprops.com

6/18/08:



	    0900 hrs/temp 58/winds calm



First day of test flights done at “Rolla National Airport”, Vichey, MO.



total flight times approx. 1.5 hrs, Hobbs 222.0



Tests were done using various props and pulley ratios. Larry Smith was  

on hand doing the prop and pulley change outs. We were looking for the  

best combination for power and smoothness. We tried a few props and I  

settled on a 3 blade 72”  IVO



6/21/08:



	   Back home in Houston.



	   1400 hrs/temp 96/winds 330 (at) 5-10mph



	    total flight time 1.2 hrs, 3 landings, Hobbs meter 223.3



I stayed in the pattern on the first flight at home in case anything  

came loose or the engine quit, I’m right over the airport.



Take off roll est (at) 350’, climb out speed 45-50, rate of climb approx  

300-400 fpm, both of which are not as strong as the 503 was.



Max speed WOT 63-67 mph. Cruise speed at est. 3400 rpm (no tach yet)  

was 52-54 mph. Cruise and max speeds are equal to the 503’s performance.



Max oil temps hit 245 -250 on a continuous max WOT climb for 5+  

minutes. Oil temps at normal cruise speeds ran 225 -235. This will  

need correction!



I could not record RPM’s today as I do not have a tach set up, waiting  

on a Tiny Tach to come in this week. My previous tach for the 503 was  

in my EIS, which must be re-programmed for the 4 stroke.



	    IVO prop setting (at) 2 turns increased pitch from neutral, or  

around 41” pitch.



Plane handling characteristics were very good, no change from 503  

Rotax other than reduced climb rate and increased take-off roll.  

However, I never flew the 503 in any temps over 82 degrees, so I’m not  

so sure the lack of climb rate isn’t partially due to the high density  

altitude conditions experienced today with 97 degree temperatures at  

take-off.



6/22/08:



0830 hrs/temp 77 to start, 90 at end of flight/winds 340 (at) 5mph



total flight time 3.6 hrs, 4 landings, Hobbs meter 226.9



take off rolls est (at) 250’, climb out speed 45-50, rate of climb avg  

350-400 fpm



avg cruise speed 52-55 mph, did not do any WOT level flight.



Max oil temps hit 245-250 on WOT climbs. Avg cruise oil temps were  

225-235. Oil temps are too high, a larger oil cooler will be needed.



Verified fuel burn avg was 1.9 gal/hr. Used 6.7 gal, 3.7 hrs engine on.



Flew a total of 163.6 miles, 5 landings.  Alvin (6R5) to Bailes (7R9)  

to Masomilliano to Brookshire (12R) to Houston Skydive to Alvin



6/23/08



1630 hrs/temp 87/winds 170 (at) 8 mph



Total flight time .7 hrs, 1 landing, Hobbs meter 227.6



No changes from the previous flights regarding take-off distance,  

climb rate, or oil temps. I changed the oil today to a synthetic 10- 

w30, oil temps were the same.



Valley Engineering is sending me a 48 plate oil cooler to replace my  

current cooler. Hopefully this should bring the oil temps down.



6/27/08



1430 hrs/temp 92/winds 150 (at)16 mph



Total flight time 1.8 hrs, 2 landings, Hobbs meter 229.4



A little windy today, but manageable flying conditions. I installed a  

“Tiny Tach” so I can now monitor my RPMs. I found my prop needs to be  

pitched stronger, as on  take off climb rpm’s were 3750-3820, at WOT  

level flight they would hit 3860-3890. Should be max rpms of  3720 on  

WOT straight & level.

6/28/08



0800 hrs/temp78/winds 170 (at) 10 mph, air temps had reached 90 at final  

landing around 2 pm.



Total flight time 1.8 hrs, 4 landings, Hobbs 231.6



Take off rpms (at) 3650, WOT rpms (at) 3730, just about right on the prop  

adjustment. Some improvement in take off distance and climb as a  

result. Climb rate was around 350-400 fpm. Improvements in cruise and  

WOT speeds, 3400 rpm cruise got 56-60 mph, WOT to 63-65 mph. At 3100  

rpm I was getting 50 mph IAS. Oil temps never got over 230. I’m happy  

with the improvements in performance with the properly adjusted prop  

pitch.



6/29/08



	    1200 hrs/temp 88/winds light & variable.



Total flight time 1 hr, 2 landings, Hobbs 232.6



Quick flight to Bailes Field in Angleton, about 22 minutes from Alvin.  

Oil temps seem to be doing slightly better each day. Never got over  

230, but never got under 220.. All the speeds and rpm numbers are  

running the same, 3000 rpm will just barely maintain straight & level,  

3300-3400 seems about right for normal cruise, ASI reads 53-58 in that  

range. Engine is performing well, nice sound, much quieter than the  

503, I can hear myself and others on the headset much better. Bailes  

has 100’ markers on the runway, and I tried a short field take-off and  

lifted the wheels right at 300 ft. Again, not as hot as the 503. Climb  

out rate with the new prop setting is running 300-400 fpm.

7/2/08



	    1600 hrs/temp 88/winds 180 (at) 10 mph



	    Total flight time 1.1 hr, 1 landing, Hobbs 234.3



Installed the larger oil cooler today and did static run ups for 30  

minutes. Oil temps never went higher than 185 degrees at WOT for  

extended time periods. I ran the engine from the stock impulse pump to  

see if it would pull fuel. Engine dies at higher rpms, so I am totally  

dependent on the elect. pump at this time.



Take off rpm still 3650, WOT rpm 3720 - 3750. No changes in any  

performance #’s, but engine oil temps are under control. I did a lot  

of extended climbs at 3600 rpm, highest oil temp reading was 180. It  

took about 3300 rpm to maintain straight and level flight today in  

very hot, muggy air.



7/4/08



	    0730 hrs/temps 76 start, 88 end/winds 190 (at) 8 mph



	    Total flight time 2.9 hrs, 4 landings, Hobbs 237.4



I took off with a max. fuel load, 12 gal. Take off roll longer than  

normal, around 400 to 450 ft, 250-350 fpm climb. Grass runway was wet  

and needs mowing. I believe the runway conditions along with max fuel  

weight added substantially to take-off distance. The goal today was to  

go on a 3 hr minimum flight. Weather was nice and smooth until the  

last hour of flight when Gulf showers started building and it got  

turbulent.



Oil temps are staying at 175-180 regardless of cruise or climb rpms.  

3300 to 3450 looks like the best cruise rpms, with airspeeds at 54-58  

mph. Plane handled nicely. I did 2 take-offs/landings at Angleton on a  

well -mowed dry grass strip with 100’ markers. I needed to prepare for  

my upcoming Nauga Fly-In trip which has 1450 ft. runways with 80’  

trees at both ends. Take off roll was 300 -350 ft, and  I estimated I  

could clear an 80 ft. obstacle at 1100-1200 ft.

I flew a total of 140 miles departing Alvin Airpark (6r5), landed at  

Bay City (BYY), on to the Texas coast, turning NE to Freeport, north  

to do landings at  Angleton, (7R9) and back to Alvin.



7/6/08



	     0800 hrs/temp 77 start, 91 end/winds 150 (at) 11



Total flight time 4 hrs, 4 landings, Hobbs 241.6



Take off roll 400, 300-400 fpm climb out. All performance data is  

staying the same.



I flew from Alvin to Brookshire, (12R) topped off fuel there and  

headed west to 10 miles short of Columbus, had rain clouds ahead so  

turned SE to the San Bernard River, following it SE to Wharton County,  

from there E to Angleton, then back to Alvin. Worked on the plane a  

bit and flew for another hour local.



7/13 & 14/08



0700 hrs/temp 81 start, 94 end/winds 210 (at) 12



Total flight time for 2 days, 12.3 hrs, 9 landings, 610 miles, Hobbs  

253.9



I flew to the Nauga Fly-In, St. Francisville LA, hosted by John  

Bickham.  The engine performed fine throughout the trip, with the  

exception of climb out rates. Went through 26.05 gal of fuel, avg.  

2.12/gph. The maximum altitude I flew at was 4500’ heading home. The  

engine wants to cruise between 3350 and 3420 rpm.



Nauga Field is 1450’ long with 80’ trees at both ends. I was concerned  

with my reduced climb out rate at this field. I had 4 gal of fuel on  

board and no extra baggage. I successfully took off 2 times out of  

Nauga, first one at 6 pm with temps in the low 90’s, second one at 8  

am Sunday with the temps near 75. I would guess I cleared the trees by  

50’ on both take-offs. It felt closer than that and may have been. I  

would not want to take off there in my plane with this engine on a  

regular basis. This type of field is where the engine needs 10 to 15  

more HP.   On any field with minimum 1000’ lengths and no obstructions  

it is fine, but in tight holes like Nauga it is tough. The 503 would  

have blasted out of there without any problem.



Engine Summary:



Total testing hrs, 34

Avg fuel burn, 2 gph

best cruise rpm, 3300-3450, producing 53-58 mph.

3600 rpm climb out, avg 250-400 fpm

3730 rpm WOT straight & level flight, top speed 67 mph.

Minimum rpm required to maintain altitude, around 3000, dependent on air

Max oil temp, 180

Cost, including prop, installation, and necessary engine mount fab  

work, $5200.00

Estimated TBO is 1500 hrs.



End of Engine Testing Report



In summary, I'm happy with my purchase. Gene and Larry Smith were  

great help and did a super job, and I would highly recommend them.  

They are working on a turbo-charged version which hopefully will come  

together over the next year. That may add the additional 10 -15 HP  

which should improve the climb out rate, the only drawback in  

performance I have experienced with this engine vs. the 503. If you  

have to climb out of tight strips all the time, this is not the engine  

for you. However if you regularly fly from fields with little or no  

obstructions, I think it's a good alternative. The best bonus is, I  

have doubled my range without adding fuel tanks. 2 gph is nice.



Jimmy Young

Kolb FS II

N7043P

Houston, TX

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_________________
Jimmy Young
Missouri City, TX
Kolb FS II/HKS 700

NeilsenRM(at)comcast.net
Guest

Posted: Tue Jul 15, 2008 6:06 pm Post subject: Generac engine test data on my FS II

Jimmy



Thanks so much for the report.



Rick Neilsen

Redrive VW powered MKIIIC



---

George Alexander

Joined: 10 Jan 2006
Posts: 245
Location: SW Florida

Posted: Wed Jul 16, 2008 5:00 am Post subject: Re: Generac engine test data on my FS II

Jimmy:

For the benefit of those of us who are still tied to the R503s......

Was there a determination made as to what caused yours to fail?

Thanks,



 	  Jimmy Young wrote: 	
		  Hi to all,



Last Memorial Day weekend I had an engine failure on my Rotax 503.  

landed off-field with no problems other than a change of underwear. My  

503 had 205 hrs. on it when it failed. I had been contemplating  

getting a 4 stroke engine when my 300 hr. rebuild came due, so this  

just sped up the process. 

<<<<SNIP>>>>



Jimmy Young

Kolb FS II

N7043P

Houston, TX

_________________
George Alexander
FS II R503
E-LSA N709FS
http://www.oh2fly.net

ez(at)embarqmail.com
Guest

Posted: Wed Jul 16, 2008 5:19 am Post subject: Generac engine test data on my FS II

Jimmy,



Does your plane still have the wing fold capability, or are there some  

interference problems with the engine?



Gene

On Jul 15, 2008, at 7:05 PM, Jimmy Young wrote:



 	  Quote: 	
		   Hi to all,



 Last Memorial Day weekend I had an engine failure on my Rotax 503.  

 landed off-field with no problems other than a change of underwear.  

 My 503 had 205 hrs. on it when it failed. I had been contemplating  

 getting a 4 stroke engine when my 300 hr. rebuild came due, so this  

 just sped up the process. I was considering the HKS 700 and the  

 Generac V-twin from Valley Engineering. The cost difference was  

 substantial, so much so that I figured I would rather spend a little  

 more and get a Mark III than get the HKS. I decided to further  

 investigate the Generac.



 I contacted Dick Stark in Kansas City, who owns a Kolb Mark II with  

 the Generac engine. He let me come up to see the engine & hear it  

 run, and would have flown it but the weather was bad. It sounded and  

 felt great. He and his wife Sharon, who usually flies the Kolb, were  

 very happy with it, so I drove to Valley Engineering in Rolla MO to  

 see more. I was impressed with the operation and the people who own  

 it, Gene and Larry Smith. They had done the install on Dick's plane,  

 and I decided to order one.



 The week of June 16th I trailered my plane to Rolla and they started  

 the install. There are mods that were done to the engine mount area  

 that required welding some 4130 angle and plate steel. The engine is  

 installed direct to the frame with no shock mounts. This is done to  

 control the "torsional resonance" a V-type engine can produce,  

 according to Gene Smith. I'm no expert in any of that, and don't  

 profess to be. I leave that up to people like the Smiths who do it  

 professionally on a daily basis. I do know that I feel no more  

 vibration in my plane now than when it had the 503. By Wednesday  

 morning we were doing test flights at Vichey Field, also known as  

 Rolla National Airport. We tried 3 different props and redrive  

 ratios, and I went with the IVO 3 blade 72" with a 2.0 redrive. I  

 headed home with my new engine ready to start running it through a  

 testing period. The following information contains all of the  

 performance data I have compiled over the last 3 1/2 weeks and the  

 first 34 hrs. of flight with the new engine:



 Flight Test Notes on a new Generac V-Twin engine from Valley  

 Engineering, Rolla, MO.

 Reduction Drive: 2.0, belt driven

 Prop: IVO 72” 3 blade

 HP: 40 at 3600 rpm

 single Weber carb with accelerator pump, no choke or primer.

 This engine is replacing a Rotax 503 DCDI.

 My FS II weighs 435 lbs empty, no fuel.

 For more engine information, see www.culverprops.com

 6/18/08:



 	    0900 hrs/temp 58/winds calm



 First day of test flights done at “Rolla National Airport”, Vichey,  

 MO.



 total flight times approx. 1.5 hrs, Hobbs 222.0



 Tests were done using various props and pulley ratios. Larry Smith  

 was on hand doing the prop and pulley change outs. We were looking  

 for the best combination for power and smoothness. We tried a few  

 props and I settled on a 3 blade 72”  IVO



 6/21/08:



 	   Back home in Houston.



 	   1400 hrs/temp 96/winds 330 (at) 5-10mph



 	    total flight time 1.2 hrs, 3 landings, Hobbs meter 223.3



 I stayed in the pattern on the first flight at home in case anything  

 came loose or the engine quit, I’m right over the airport.



 Take off roll est (at) 350’, climb out speed 45-50, rate of climb  

 approx 300-400 fpm, both of which are not as strong as the 503 was.



 Max speed WOT 63-67 mph. Cruise speed at est. 3400 rpm (no tach yet)  

 was 52-54 mph. Cruise and max speeds are equal to the 503’s  

 performance.



 Max oil temps hit 245 -250 on a continuous max WOT climb for 5+  

 minutes. Oil temps at normal cruise speeds ran 225 -235. This will  

 need correction!



 I could not record RPM’s today as I do not have a tach set up,  

 waiting on a Tiny Tach to come in this week. My previous tach for  

 the 503 was in my EIS, which must be re-programmed for the 4 stroke.



 	    IVO prop setting (at) 2 turns increased pitch from neutral, or  

 around 41” pitch.



 Plane handling characteristics were very good, no change from 503  

 Rotax other than reduced climb rate and increased take-off roll.  

 However, I never flew the 503 in any temps over 82 degrees, so I’m  

 not so sure the lack of climb rate isn’t partially due to the high  

 density altitude conditions experienced today with 97 degree  

 temperatures at take-off.



 6/22/08:



 0830 hrs/temp 77 to start, 90 at end of flight/winds 340 (at) 5mph



 total flight time 3.6 hrs, 4 landings, Hobbs meter 226.9



 take off rolls est (at) 250’, climb out speed 45-50, rate of climb avg  

 350-400 fpm



 avg cruise speed 52-55 mph, did not do any WOT level flight.



 Max oil temps hit 245-250 on WOT climbs. Avg cruise oil temps were  

 225-235. Oil temps are too high, a larger oil cooler will be needed.



 Verified fuel burn avg was 1.9 gal/hr. Used 6.7 gal, 3.7 hrs engine  

 on.



 Flew a total of 163.6 miles, 5 landings.  Alvin (6R5) to Bailes  

 (7R9) to Masomilliano to Brookshire (12R) to Houston Skydive to Alvin



 6/23/08



 1630 hrs/temp 87/winds 170 (at) 8 mph



 Total flight time .7 hrs, 1 landing, Hobbs meter 227.6



 No changes from the previous flights regarding take-off distance,  

 climb rate, or oil temps. I changed the oil today to a synthetic 10- 

 w30, oil temps were the same.



 Valley Engineering is sending me a 48 plate oil cooler to replace my  

 current cooler. Hopefully this should bring the oil temps down.



 6/27/08



 1430 hrs/temp 92/winds 150 (at)16 mph



 Total flight time 1.8 hrs, 2 landings, Hobbs meter 229.4



 A little windy today, but manageable flying conditions. I installed  

 a “Tiny Tach” so I can now monitor my RPMs. I found my prop needs to  

 be pitched stronger, as on  take off climb rpm’s were 3750-3820, at  

 WOT level flight they would hit 3860-3890. Should be max rpms of   

 3720 on WOT straight & level.

 6/28/08



 0800 hrs/temp78/winds 170 (at) 10 mph, air temps had reached 90 at  

 final landing around 2 pm.



 Total flight time 1.8 hrs, 4 landings, Hobbs 231.6



 Take off rpms (at) 3650, WOT rpms (at) 3730, just about right on the prop  

 adjustment. Some improvement in take off distance and climb as a  

 result. Climb rate was around 350-400 fpm. Improvements in cruise  

 and WOT speeds, 3400 rpm cruise got 56-60 mph, WOT to 63-65 mph. At  

 3100 rpm I was getting 50 mph IAS. Oil temps never got over 230. I’m  

 happy with the improvements in performance with the properly  

 adjusted prop pitch.



 6/29/08



 	    1200 hrs/temp 88/winds light & variable.



 Total flight time 1 hr, 2 landings, Hobbs 232.6



 Quick flight to Bailes Field in Angleton, about 22 minutes from  

 Alvin. Oil temps seem to be doing slightly better each day. Never  

 got over 230, but never got under 220.. All the speeds and rpm  

 numbers are running the same, 3000 rpm will just barely maintain  

 straight & level, 3300-3400 seems about right for normal cruise, ASI  

 reads 53-58 in that range. Engine is performing well, nice sound,  

 much quieter than the 503, I can hear myself and others on the  

 headset much better. Bailes has 100’ markers on the runway, and I  

 tried a short field take-off and lifted the wheels right at 300 ft.  

 Again, not as hot as the 503. Climb out rate with the new prop  

 setting is running 300-400 fpm.

 7/2/08



 	    1600 hrs/temp 88/winds 180 (at) 10 mph



 	    Total flight time 1.1 hr, 1 landing, Hobbs 234.3



 Installed the larger oil cooler today and did static run ups for 30  

 minutes. Oil temps never went higher than 185 degrees at WOT for  

 extended time periods. I ran the engine from the stock impulse pump  

 to see if it would pull fuel. Engine dies at higher rpms, so I am  

 totally dependent on the elect. pump at this time.



 Take off rpm still 3650, WOT rpm 3720 - 3750. No changes in any  

 performance #’s, but engine oil temps are under control. I did a lot  

 of extended climbs at 3600 rpm, highest oil temp reading was 180. It  

 took about 3300 rpm to maintain straight and level flight today in  

 very hot, muggy air.



 7/4/08



 	    0730 hrs/temps 76 start, 88 end/winds 190 (at) 8 mph



 	    Total flight time 2.9 hrs, 4 landings, Hobbs 237.4



 I took off with a max. fuel load, 12 gal. Take off roll longer than  

 normal, around 400 to 450 ft, 250-350 fpm climb. Grass runway was  

 wet and needs mowing. I believe the runway conditions along with max  

 fuel weight added substantially to take-off distance. The goal today  

 was to go on a 3 hr minimum flight. Weather was nice and smooth  

 until the last hour of flight when Gulf showers started building and  

 it got turbulent.



 Oil temps are staying at 175-180 regardless of cruise or climb rpms.  

 3300 to 3450 looks like the best cruise rpms, with airspeeds at  

 54-58 mph. Plane handled nicely. I did 2 take-offs/landings at  

 Angleton on a well -mowed dry grass strip with 100’ markers. I  

 needed to prepare for my upcoming Nauga Fly-In trip which has 1450  

 ft. runways with 80’ trees at both ends. Take off roll was 300 -350  

 ft, and  I estimated I could clear an 80 ft. obstacle at 1100-1200 ft.

 I flew a total of 140 miles departing Alvin Airpark (6r5), landed at  

 Bay City (BYY), on to the Texas coast, turning NE to Freeport, north  

 to do landings at  Angleton, (7R9) and back to Alvin.



 7/6/08



 	     0800 hrs/temp 77 start, 91 end/winds 150 (at) 11



 Total flight time 4 hrs, 4 landings, Hobbs 241.6



 Take off roll 400, 300-400 fpm climb out. All performance data is  

 staying the same.



 I flew from Alvin to Brookshire, (12R) topped off fuel there and  

 headed west to 10 miles short of Columbus, had rain clouds ahead so  

 turned SE to the San Bernard River, following it SE to Wharton  

 County, from there E to Angleton, then back to Alvin. Worked on the  

 plane a bit and flew for another hour local.



 7/13 & 14/08



 0700 hrs/temp 81 start, 94 end/winds 210 (at) 12



 Total flight time for 2 days, 12.3 hrs, 9 landings, 610 miles, Hobbs  

 253.9



 I flew to the Nauga Fly-In, St. Francisville LA, hosted by John  

 Bickham.  The engine performed fine throughout the trip, with the  

 exception of climb out rates. Went through 26.05 gal of fuel, avg.  

 2.12/gph. The maximum altitude I flew at was 4500’ heading home. The  

 engine wants to cruise between 3350 and 3420 rpm.



 Nauga Field is 1450’ long with 80’ trees at both ends. I was  

 concerned with my reduced climb out rate at this field. I had 4 gal  

 of fuel on board and no extra baggage. I successfully took off 2  

 times out of Nauga, first one at 6 pm with temps in the low 90’s,  

 second one at 8 am Sunday with the temps near 75. I would guess I  

 cleared the trees by 50’ on both take-offs. It felt closer than that  

 and may have been. I would not want to take off there in my plane  

 with this engine on a regular basis. This type of field is where the  

 engine needs 10 to 15 more HP.   On any field with minimum 1000’  

 lengths and no obstructions it is fine, but in tight holes like  

 Nauga it is tough. The 503 would have blasted out of there without  

 any problem.



 Engine Summary:



 Total testing hrs, 34

 Avg fuel burn, 2 gph

 best cruise rpm, 3300-3450, producing 53-58 mph.

 3600 rpm climb out, avg 250-400 fpm

 3730 rpm WOT straight & level flight, top speed 67 mph.

 Minimum rpm required to maintain altitude, around 3000, dependent on  

 air

 Max oil temp, 180

 Cost, including prop, installation, and necessary engine mount fab  

 work, $5200.00

 Estimated TBO is 1500 hrs.



 End of Engine Testing Report



 In summary, I'm happy with my purchase. Gene and Larry Smith were  

 great help and did a super job, and I would highly recommend them.  

 They are working on a turbo-charged version which hopefully will  

 come together over the next year. That may add the additional 10 -15  

 HP which should improve the climb out rate, the only drawback in  

 performance I have experienced with this engine vs. the 503. If you  

 have to climb out of tight strips all the time, this is not the  

 engine for you. However if you regularly fly from fields with little  

 or no obstructions, I think it's a good alternative. The best bonus  

 is, I have doubled my range without adding fuel tanks. 2 gph is nice.



 Jimmy Young

 Kolb FS II

 N7043P

 Houston, TX



 <moz-screenshot-71.jpg><moz-screenshot-68.jpg><moz-screenshot-69.jpg>

rlaird

Joined: 10 Jan 2006
Posts: 373
Location: Houston

Posted: Wed Jul 16, 2008 8:25 am Post subject: Generac engine test data on my FS II

Jimmy will correct me if I'm wrong, but I think I remember him telling me it was a wrist pin failure.

On Wed, Jul 16, 2008 at 8:00 AM, George Alexander <gtalexander(at)att.net (gtalexander(at)att.net)> wrote:

  	  Quote: 	
		  --> Kolb-List message posted by: "George Alexander" <gtalexander(at)att.net (gtalexander(at)att.net)>

 Jimmy:

 For the benefit of those of us who are still tied to the R503s......

 Was there a determination made as to what caused yours to fail?

 Thanks,

 Jimmy Young wrote:

 > Hi to all,

 >

 > Last Memorial Day weekend I had an engine failure on my Rotax 503.

 > landed off-field with no problems other than a change of underwear. My

 > 503 had 205 hrs. on it when it failed. I had been contemplating

 > getting a 4 stroke engine when my 300 hr. rebuild came due, so this

 > just sped up the process.

 >

 >

 >

 >

 >

 >

 > Jimmy Young

 > Kolb FS II

 > N7043P

 > Houston, TX

 --------

 George Alexander

 FS II R503  N709FS

 http://gtalexander.home.att.net

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=193068#193068

-- 

Why did the chicken cross the Mobius strip? To get to the other, er, um....

  [quote][b]

_________________
~~~~~~~~~~~~~~~~~~~
Robert Laird
formerly: MkIIIc w/ 912ULS & Gyrobee
current: Autogyro Cavalon w/ 914ULS
Houston, TX area
http://www.Texas-Flyer.com

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Jul 16, 2008 8:59 am Post subject: Re: Generac engine test data on my FS II

Your detailed reports on the Genrac engine are very good information for anyone that is considering using something other than a 503 on a Firestar.   Unfortunately, given your reports this seems to be a very poor engine choice for a Kolb. 



The very poor climb rate with the Genrac engine leaves you very vulnerable on takeoff, if you lose the engine on takeoff you will find yourself much lower, and with less landing options than you would with the 503 or with the HKS.



Belt re-drives for props are notorious for being unreliable and points of failure, I would not buy any engine that used a belt re-drive for the prop.  Being dependent on the electric fuel pump is not a great thing, electric pumps themselves are extremely dependable, the the electrical systems that drive them are not.   The electric facet pump is also very sensitive to any kind of debris in the fuel stopping it from pumping, make sure you have a good fuel filter before that pump.



Given the high price of the Genrac engine, spending a little extra for the HKS would be a no brainer for me.  The extra reliability, extra power, and extra safety of the HKS all make it a much better engine choice for a Kolb, even if it is about 3000 dollars more.



JettPilot

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

Jimmy Young

Joined: 24 Nov 2007
Posts: 182
Location: Missouri City, TX

Posted: Wed Jul 16, 2008 9:34 am Post subject: Generac engine test data on my FS II

Eugene Zimmerman asked:



 >Does your plane still have the wing fold capability?<



Eugene,



I have to remove the oil filter to fold the right wing, but I just  

tape a baggie over the opening and it's easy to do. I very rarely fold  

it since I keep it in a hanger.



George Alexander asked:



 >Was there a determination made as to what caused the 503 to fail?<



George,



Some of the local guys in my flying club think the wrist pin failed or  

the "circlip" came loose, causing the #1piston to get damaged. The  

piston skirt was broken off all the way around and the engine was full  

of ground up aluminum. The 503 had 205 hrs. on it at the time of it's  

demise and was running perfectly up until about 1 second before it  

quit. I've been busy doing other things, but one day I'll get around  

to looking inside and let you know what we found. I'm attaching a  

photo of the front cylinder looking thru the intake manifold.



Jimmy Y

FSCN0203.jpg

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_________________
Jimmy Young
Missouri City, TX
Kolb FS II/HKS 700

ez(at)embarqmail.com
Guest

Posted: Wed Jul 16, 2008 9:48 am Post subject: Generac engine test data on my FS II

On Jul 16, 2008, at 12:59 PM, JetPilot wrote:



 	  Quote: 	
		   Given the high price of the Genrac engine, spending a little extra  

 for the HKS would be a no brainer for me.


	




Unlike you, not all Kolb pilots  operate by the "no brainer"  principle.

Homer himself being chief among them.

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Jul 16, 2008 10:22 am Post subject: Re: Generac engine test data on my FS II

 	  ez(at)embarqmail.com wrote: 	
		  



Unlike you, not all Kolb pilots  operate by the "no brainer"  principle.

Homer himself being chief among them.



	




Just in case you have a problem understanding simple English, " No brainer " in this scentence means " Easy Choice ", not a principle.



Given the data, the HKS is clearly a much superrior engine to the genrac, and it is an easy choice between the two.  



If you honestly disagree, then sign your name to your post, and go out and buy a genrac to put on your firestar.   If on the other hand, you are just trying distract readers from the facts, then don't sign your name, and do as you are doing.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

herbgh(at)nctc.com
Guest

Posted: Wed Jul 16, 2008 10:52 am Post subject: Generac engine test data on my FS II

Nice thing about the Generac is that it can be bought stock for 

little over 2k..Likely found at the salvage yard in need of an 

overhaul in the coming months and years...They usually sell by weight 

there..100 lbs would be 20 dollars currently...have my eyes 

open...    the other thing is that the Valley redirve is not 

rocket science and can be duplicated for 500 bucks by someone with a 

lathe and mill and the skill.. I like the multi vee belt ...Have used 

them with good servicability in the past.. My G50 Zenoah had one...My 

buddies flying F23 Hirth engines use them also..

    I can see,therefore, that the Generac can be flying by someone 

with a modicum of mechanical skill for a lot less than the 5k or so 

that Valley Engineering wants..  A trade off to be sure...but not a 

bad one...lots of planes fall into the 4 to 500 ft per minute rate of 

climb...  My little N3 Pup for one...has a half vw...less than 2 gph 

.  Great little bird... Herb

At 01:22 PM 7/16/2008, you wrote:

 	  Quote: 	

ez(at)embarqmail.com wrote:

 >

 >

 > Unlike you, not all Kolb pilots  operate by the "no brainer"  principle.

 > Homer himself being chief among them.

 >

 >

Just in case you have a problem understanding simple English, " No 

brainer " in this scentence means " Easy Choice ", not a principle.

Given the data, the HKS is clearly a much superrior engine to the 

genrac, and it is an easy choice between the two.

If you disagree, then sign your name to your post, and go out and 

buy a genrac to put on your firestar, you will deserve the results you get.

Mike

--------

&quot;NO FEAR&quot; -  If you have no fear you did not go as fast as 

you could have !!!

Kolb MK-III Xtra, 912-S

Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=193148#193148

bartmo(at)sbcglobal.net
Guest

Posted: Wed Jul 16, 2008 11:18 am Post subject: Generac engine test data on my FS II

Have you checked the installed price of a HKS recently?

  It is going to be almost $11000.00

  Bart Morgan

  FS II [in progress]

   

   

   

  Do not archive

JetPilot <orcabonita(at)hotmail.com> wrote:

  [quote]--> Kolb-List message posted by: "JetPilot" 



Your detailed reports on the Genrac engine are very good information for anyone that is considering using something other than a 503 on a Firestar. Unfortunately, given your reports this seems to be a very poor engine choice for a Kolb. 



The very poor climb rate with the Genrac engine leaves you very vulnerable on takeoff, if you lose the engine on takeoff you will find yourself much lower, and with less landing options than you would with the 503 or with the HKS.



Belt  re-drives for props are notorious for being unreliable and points of failure, I would not buy any engine that used a belt re-drive for the prop. Being dependent on the electric fuel pump is not a great thing, electric pumps themselves are extremely dependable, the the electrical systems that drive them are not. The electric facet pump is also very sensitive to any kind of debris in the fuel stopping it from pumping, make sure you have a good fuel filter before that pump.



Given the high price of the Genrac engine, spending a little extra for the HKS would be a no brainer for me. The extra reliability, extra power, and extra safety of the HKS all make it a much better engine choice for a Kolb, even if it is about 3000 dollars more.



JettPilot



--------

"NO FEAR" - If you have no fear you did not go as fast as you could have !!!



Kolb MK-III Xtra, 912-S





Read this topic online [quote][b]

slyck(at)frontiernet.net
Guest

Posted: Wed Jul 16, 2008 11:22 am Post subject: Generac engine test data on my FS II

If it's a principle we are looking for, it comes under the "different  

strokes for.....etc"

A compromise will be found by a sensible guy to do what works best  

for him.

Sure a 912 would be superior engine to my suzuki, but my type of  

flying, just casual jaunts

in the countryside and evening rides, makes a (much) cheaper mill  

perfectly suitable.



I have no need for 1200' climb, especially here at 600' msl.  You can  

always find a faster,

more powerful, more agile airplane, Barnstormers has lots of them.



I check the radiator and the dipstick and what's wiggling loose and  

that's it for maintenance.

I don't plan on ever overhauling it again.



I think the generac will attract more builders.

BB



On 16, Jul 2008, at 2:22 PM, JetPilot wrote:



 	  Quote: 	
		   

 ez(at)embarqmail.com wrote:

> Unlike you, not all Kolb pilots  operate by the "no brainer"   

> principle.

> Homer himself being chief among them.

 Just in case you have a problem understanding simple English, " No  

 brainer " in this scentence means " Easy Choice ", not a principle.



 Given the data, the HKS is clearly a much superrior engine to the  

 genrac, and it is an easy choice between the two.



 If you disagree, then sign your name to your post, and go out and  

 buy a genrac to put on your firestar, you will deserve the results  

 you get.



 Mike



 --------

 &quot;NO FEAR&quot; -  If you have no fear you did not go as fast  

 as you could have !!!



 Kolb MK-III Xtra, 912-S





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=193148#193148

NeilsenRM(at)COMCAST.NET
Guest

Posted: Wed Jul 16, 2008 12:01 pm Post subject: Generac engine test data on my FS II

Mike(jetPilot)



You tend to get all wound up in expressing your opinions. It would also be 

nice to know were you have gained such iron clad knowledge.



I for one think this is wonderful. A affordable reliable engine alternative 

for a Firestar II. Knowing how those redrives work the load on the engine is 

the same as the load it would encounter as a generator maybe even less. 

These engines run hundreds if not thousands of hours with very limited 

maintenance so they should be very reliable. I would expect that if there 

were problems with the Generac engine you would see it coming hundreds of 

hours before it would fail, with the possible exception of failure within 

the first few hours of use.



I use the same type of redrive on my VW and can't understand how they could 

be unreliable. They do require some maintenance and tuning from time to 

time. It's just something you work with like changing oil or spark plugs. I 

would venture a guess that you could see a belt wearing to the point of 

failure easer than a Rotax driver could see those rubber carburetor sockets 

getting ready to throw a carb.



As for the HKS I watched the HKS distributor try to fix his HKS in a Kit Fox 

for hours after it got sick a few miles out of Oshkosh. It was just teething 

issues but even that engine isn't bullet proof.



I also have a electric only fuel pump on my VW. I would prefer a mechanical 

pump with a electric backup but I have tried to minimize the failure 

potential with two electric pumps with two electric sources.



Rick Neilsen

Redrive VW powered MKIIIC





---

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed Jul 16, 2008 1:05 pm Post subject: Generac engine test data on my FS II

> I for one think this is wonderful. A affordable reliable engine 

alternative

 	  Quote: 	
		   for a Firestar II. Knowing how those redrives work the load on the engine 

 is the same as the load it would encounter as a generator maybe even less. 

 These engines run hundreds if not thousands of hours with very limited 

 maintenance so they should be very reliable.

 Rick Neilsen


	




Hi Rick:



I think I'll sit back and watch the hours being amassed on the Generac and 

redrive before I decide how affordable and reliable it really is compared to 

the alternatives that are out there now.



The Generac powered FS barely made it out of Nauga Field, 1500 ft grass, 40 

ft ASL, empty.   I'm not knocking my good friend Jimmy Young or his power 

plant and redrive.  Simply stating what I observed.  Two GPH is great fuel 

economy, but cutting the fuel burn in half has also cut the performance in 

half.  Personally, I would perfer more performance.



The performance and reliability data base on the Generac, powering an 

airplane, is probably pretty small.  Will take a while for it to present 

some realistic figures.



Now.......two Generacs on a FS would be the way to go.  



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Ricochet

Joined: 29 May 2008
Posts: 36
Location: Fresno, CA

Posted: Wed Jul 16, 2008 1:21 pm Post subject: Generac engine test data on my FS II

....and, Robert (BB), what do you have your Suzuki mounted on, how's  

you like it, how's it perform?



Former Firestar (503) driver, Kolb aficionado/wannabee(?),



Jerry

 	  Quote: 	
		  

 If it's a principle we are looking for, it comes under the  

 "different strokes for.....etc"

 A compromise will be found by a sensible guy to do what works best  

 for him.

 Sure a 912 would be superior engine to my suzuki, but my type of  

 flying, just casual jaunts

 in the countryside and evening rides, makes a (much) cheaper mill  

 perfectly suitable.



 I have no need for 1200' climb, especially here at 600' msl.  You  

 can always find a faster,

 more powerful, more agile airplane, Barnstormers has lots of them.



 I check the radiator and the dipstick and what's wiggling loose and  

 that's it for maintenance.

 I don't plan on ever overhauling it again.



 I think the generac will attract more builders.

 BB

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Jul 16, 2008 2:02 pm Post subject: Re: Generac engine test data on my FS II

Rick,



I have seen and known enough people that have had forced landings with belt redrive systems to know they are very weak link, even when paired with a good engine.



You even had a forced landing due to a redrive failure if I remember correctly.  One case does not make a trend, but there are many reports out there with results similar to yours  " Forced landing due to Redrive failure " ...  Due to



Belts broken unexpectedly.

Bearings failing suddenly.

Pulleys coming loose 

Harmonic Problems

 

Failures of the redrive for different engines is typical  for many engine - redrive combinations.  The Genrac may be very reliable in generators, or maybe not, most generator operators do not report their reliability problems.  If the belt drive quits on a generator, it is a simple and cheap repair that you never hear anything about.   We definitelyy do not know how reliable the Genrac is on airplanes yet ( Redrive ).  Haven marginal power is a proven safety hazard in airplanes, we know that much right now, add that to the historic problems with a Redrive and it starts to look like a really bad option.   At 5000 dollars the Genrac is not by any means a cheap engine.  If is was going to spend that much money on an engine I would just spend the extra 3000 dollars and get an engine with the performance, and proven reliability of the HKS.



I have a lot of respect for Jimmy posting very honest and good performance information on the Genrac engine, it is exactly what this list is all about, so that others can learn and make whatever engine choice is right for their Kolb.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

NeilsenRM(at)comcast.net
Guest

Posted: Wed Jul 16, 2008 5:34 pm Post subject: Generac engine test data on my FS II

John/Mike



You guys are right it is too early to claim the the package is ready for 

everybody. I want it so much that I get carried away but Jimmy is on the 

right track. I have a feeling that there is more performance available with 

other prop redrive ratios. Proper prop selection is a very difficult and 

expensive task.  I also agree that a Kolb is something less than a Kolb when 

under powered. Maybe there will be more powerful alternative engines at some 

point. I watched the Genrac powered PPC fly at Sun N Fun and I was struck 

with how refined that engine starts and runs.



Yes I did have a redrive mount crack causing a forced landing a few years 

ago I never made a secret of it. This was primarily caused by me using a 

prop that wasn't recommended. Gene and Larry Smith at Valley have really 

tried to build reliable redrives. They stand behind their redrives and I 

know they fix any problems that turn up. The redrive that had the bracket 

failure was a series two redrive. The bracket on my original redrive that 

cracked was 3\8 thick and all the new ones are 5\8 thick. The new series 

three redrive I have has two belts each capable of driving the redrive. The 

bearings on the my redrive are automotive front wheel drive wheel bearings 

designed so that they are more than capable of the mission. Also these 

redrives are heavily tested on airboats or their prop powered buggy before 

they are ever put on a airplane. We have discussed belt redrives before and 

if you can't except that they can be reliable don't buy them.



Rick Neilsen

Redrive VW powered MKIIIC



---

gaman(at)att.net
Guest

Posted: Wed Jul 16, 2008 6:31 pm Post subject: Generac engine test data on my FS II

Some certified aircraft fly with belt redrives everyday.Brantly comes to mind first



---

Mnflyer

Joined: 15 May 2006
Posts: 78

Posted: Wed Jul 16, 2008 8:08 pm Post subject: Re: Generac engine test data on my FS II

"Some certified aircraft fly with belt redrives everyday.Brantly comes to mind first"

If you are referring to the Brantly Helicopter, it is not belt driven, but the Engstrom and the Hughes 269 helicopters are belt driven

In fact the Engstrom turbine power helicopter has a 420 shp  turbine engine that is belt driven.

_________________
GB
MNFlyer
Flying a HKS Kitfox III

slyck(at)frontiernet.net
Guest

Posted: Wed Jul 16, 2008 8:36 pm Post subject: Generac engine test data on my FS II

Enstrom had a big wide special use belt.  A failure was  

catastrophic.  The Hughes series

uses several v belts that offer some redundancy.  The early models  

had a manual clutch

to engage the belts and the later ones had an electric engagement  

device  (click a switch

momentarily on and off until the rotor started to grab)

I believe that belt system was fairly reliable and  easy to visually  

inspect on preflight.

BB

do not archive



On 17, Jul 2008, at 12:08 AM, Mnflyer wrote:



 	  Quote: 	
		   



 "Some certified aircraft fly with belt redrives everyday.Brantly  

 comes to mind first"

 If you are referring to the Brantly Helicopter, it is not belt  

 driven, but the Engstrom and the Hughes 269 helicopters are belt  

 driven



 --------

 GB

 MNFlyer

 Flying a HKS Kitfox III





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=193294#193294

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