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Trying an unproven engine - is it feasible, is it safe?
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AB_Summit

Joined: 16 Jul 2007
Posts: 23

Posted: Thu Dec 27, 2007 9:24 am Post subject: Trying an unproven engine - is it feasible, is it safe?

Hi everyone,



(This is a cross posting from homebuiltairplanes.com, but I thought I would post it here as well to get input from you guys.)



I've got an idea for a new engine redrive combination that as far as I know, no one has tried before. This is all hypothetical for the time being as I don't even have a plane to put it on, but I'm thinking of building a Zenith STOL CH-701 and I think this would be a good engine for that plane. I am not an engineer, or even a pilot yet, but I do enjoy building, fabricating, working with metal, etc.



My idea is to take a Yamaha four stroke, four cylinder snowmobile engine and adapt a Rotax gearbox redrive to it. This would be for my own personal use only and not for any commercial purpose. The engine is just under 1000cc's and produces 140HP in the carbureted version and 150HP in the EFI version, but I would derate it for aircraft use. The weight of the engine is 118 lbs. This engine is based on the R1 motorcycle engine, but doesn't have a gearbox like the motorcycle engine does. This engine has proven durable in snowmobiles that have been turbocharged and are making 300HP+.



My method of adapting the redrive to the engine would be to machine an adapter ring and coupling. There is a ring of 6 bolts around the output shaft of the engine, I could make a plate that attaches to the engine using these 6 bolts and then drill and tap the plate to accept the Rotax gearbox bolt pattern and bolt the gearbox to the plate. Then I would need to do some machining to get the shafts couple properly.



As I said in the title, my questions are would this be feasible, and would this be safe? My first thought is that if this was easy to do, somebody would have already done it, and since I haven't seen this combination before it makes me wonder if there is some problem I haven't thought of.



To me the main concerns are whether the joint between the engine and gearbox would be substantial enough to handle the load put on it by the thrust of the propeller, and whether there would be any torsional vibration concerns that would damage the engine or the gearbox. There is a rubber cushion built into the Rotax C gearbox that would help absorb some of the vibration, and there is also a clutch that can be installed into it to uncouple the gearbox from the engine at low RPM's. I could also install some external bracing between the engine and gearbox to take some of the thrust loads. Another concern is designing an engine mount that is safe and will take all the loads put on it.



If I were to go ahead with this, how could I ensure that my installation is safe? Should it be inspected by a mechanical engineer? I imagine having it looked at by an EAA tech counsellor would be a good idea as well.



Are there any risks that I haven't though of that I should be aware of? I'd like to hear your thoughts as to whether this is doable and safe. Would I be better off going with a more proven conversion like the Suzuki/Geo or go with the 912?



Thanks

Randy

John Bolding

Joined: 23 May 2006
Posts: 281

Posted: Thu Dec 27, 2007 10:42 am Post subject: Trying an unproven engine - is it feasible, is it safe?

The can of worms you've just opened is the size of a 55 gal. barrel, good 

luck !!

John



 	  Quote: 	
		   



 Hi everyone,



 (This is a cross posting from homebuiltairplanes.com, but I thought I 

 would post it here as well to get input from you guys.)



 I've got an idea for a new engine redrive combination that as far as I 

 know, no one has tried before. This is all hypothetical for the time being 

 as I don't even have a plane to put it on, but I'm thinking of building a 

 Zenith STOL CH-701 and I think this would be a good engine for that plane. 

 I am not an engineer, or even a pilot yet, but I do enjoy building, 

 fabricating, working with metal, etc.



 My idea is to take a Yamaha four stroke, four cylinder snowmobile engine 

 and adapt a Rotax gearbox redrive to it. This would be for my own personal 

 use only and not for any commercial purpose. The engine is just under 

 1000cc's and produces 140HP in the carbureted version and 150HP in the EFI 

 version, but I would derate it for aircraft use. The weight of the engine 

 is 118 lbs. This engine is based on the R1 motorcycle engine, but doesn't 

 have a gearbox like the motorcycle engine does. This engine has proven 

 durable in snowmobiles that have been turbocharged and are making 300HP+.

 > Thanks

 Randy

bill_dom(at)yahoo.com
Guest

Posted: Thu Dec 27, 2007 12:13 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

Is it safe?



Short answer; No unless you are flying over the Bonneville salt flats.



Long answer; There are a lot of divisions between builders when it comes to the viability of auto conversions to power homebuild aircraft. But that is for auto conversions that are already developed, where you buy either the converted engine or the manual and parts to do the conversion yourself. However, what you're proposing is to develop your own conversion. In this case there is no much division and almost everyone would agree that it is not a good idea to engage in one, unless you have the proper qualification and be willing to throw enough money in R&D. IMHO, if you just want an inexpensive engine to power your plane, go with an establish and proven conversion.

William Dominguez

Zodiac 601XL Plans

Miami Florida

AB_Summit <rengler(at)live.ca> wrote:[quote] --> Zenith-List message posted by: "AB_Summit" 



Hi everyone,



(This is a cross posting from homebuiltairplanes.com, but I thought I would post it here as well to get input from you guys.)



I've got an idea for a new engine redrive combination that as far as I know, no one has tried before. This is all hypothetical for the time being as I don't even have a plane to put it on, but I'm thinking of building a Zenith STOL CH-701 and I think this would be a good engine for that plane. I am not an engineer, or even a pilot yet, but I do enjoy building, fabricating, working with metal, etc.



My idea is to take a Yamaha four stroke, four cylinder snowmobile engine and adapt a Rotax gearbox redrive to it. This would be for my own personal use only and not for any commercial purpose. The engine is just under 1000cc's and produces 140HP in the carbureted version and 150HP in the EFI version, but I  would derate it for aircraft use. The weight of the engine is 118 lbs. This engine is based on the R1 motorcycle engine, but doesn't have a gearbox like the motorcycle engine does. This engine has proven durable in snowmobiles that have been turbocharged and are making 300HP+.



My method of adapting the redrive to the engine would be to machine an adapter ring and coupling. There is a ring of 6 bolts around the output shaft of the engine, I could make a plate that attaches to the engine using these 6 bolts and then drill and tap the plate to accept the Rotax gearbox bolt pattern and bolt the gearbox to the plate. Then I would need to do some machining to get the shafts couple properly.



As I said in the title, my questions are would this be feasible, and would this be safe? My first thought is that if this was easy to do, somebody would have already done it, and since I haven't seen this combination before it makes me wonder if there is some problem I haven't  thought of.



To me the main concerns are whether the joint between the engine and gearbox would be substantial enough to handle the load put on it by the thrust of the propeller, and whether there would be any torsional vibration concerns that would damage the engine or the gearbox. There is a rubber cushion built into the Rotax C gearbox that would help absorb some of the vibration, and there is also a clutch that can be installed into it to uncouple the gearbox from the engine at low RPM's. I could also install some external bracing between the engine and gearbox to take some of the thrust loads. Another concern is designing an engine mount that is safe and will take all the loads put on it.



If I were to go ahead with this, how could I ensure that my installation is safe? Should it be inspected by a mechanical engineer? I imagine having it looked at by an EAA tech counsellor would be a good idea as well.



Are there any risks that I haven't though of [quote][b]

purplemoon99(at)bellsouth
Guest

Posted: Thu Dec 27, 2007 6:59 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

55 gallons is not even close, it will turn to your WORST NITEMARE! no 

mention if it doesn't kill you it will try too, every time it gets a chance 

Belive me, I know. The money?? you better havea bag full , and If you ever 

get it work ,you will be so crazy that  you can't pass a mental test so you 

won't be allowed to fly your death trap. Buy a engine that is proven and go 

on with your life....Happy New Year .  Joe N101HD 601XL/RAM      P.S. TheH D 

in N101HD  stands for Harley Davison.......

---

Joemotis(at)aol.com
Guest

Posted: Thu Dec 27, 2007 7:29 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

I    like     the     idea.   Any    favorite     links    to     the     engine    in     question?

 And for      all of  the        naysayers,     it       is called  experimental        for  a       reason!

  

 Spectacular success     is     often    measured    by     accumulated   failure      that     you are    lucky     enough to live   through.

  

 Longtime    anything that      runs    on     gasoline  builder.

  

  

  

  

  



top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

AB_Summit

Joined: 16 Jul 2007
Posts: 23

Posted: Thu Dec 27, 2007 8:09 pm Post subject: Re: Trying an unproven engine - is it feasible, is it safe?

 	  Joemotis(at)aol.com wrote: 	
		  I    like     the     idea.   Any    favorite     links    to     the     engine    in     question? 	




There's not much to be found on the Internet about this engine, it's called the Genesis 150FI, here's one link: http://www.yamaha-motor.com/sport/sno/tech_eng.aspx



Some of the other engines on that page might be adaptable for aircraft use as well.

NYTerminat(at)aol.com
Guest

Posted: Thu Dec 27, 2007 10:02 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

Here is another link where they have converted  many types of engines, you could possibly use their  gearbox       http://www.airtrike s.net/engines. shtml 

  

 Bob Spudis

  

  

  

  

 In a message dated 12/27/2007 11:11:53 P.M. Eastern Standard Time,  rengler(at)live.ca writes:

  	  Quote: 	
		  --> Zenith-List message    posted by: "AB_Summit" <rengler(at)live.ca>

Joemotis(at)aol.com    wrote:

 	  Quote: 	
		   I    like     the        idea.   Any    favorite     links       to     the     engine       in     question?


	




There's not much to be found on the    Internet about this engine, it's called the Genesis 150FI, here's one link:    http://www.yamaha-motor.com/sport/sno/tech_eng.aspx



Some of the other    engines on that page might be adaptable for aircraft use as    well.





Read this topic online    here:



http://forums.matronics.com/viewtopic.php?p=154660#154660

	


 

  



top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Fri Dec 28, 2007 3:39 am Post subject: Re: Trying an unproven engine - is it feasible, is it safe?

Safe is a pretty relative term, I like your idea, but I don't know that I'd fly in it...right away at least. 

Try these guys, it a forum for converting motorcycle engines, its the closest info that I have. The air-trike guys mentioned are also at this forum. 



http://groups.yahoo.com/group/moto-air/



Kevin

_________________
â€œAlways do what you are afraid to do.â€
R.W. Emerson (1803-1882)

"Real freedom is the sustained act of being an individual." WW - 2009

"Life is a good deal...it's worth it" Feb 1969
Dorothy McCune

cgbrt(at)mondenet.com
Guest

Posted: Fri Dec 28, 2007 7:37 am Post subject: Trying an unproven engine - is it feasible, is it safe?

Hi Randy.

Two 701 builders here in Ottawa Cda are using the 4 cyl 4 cycle Yamaha 

engine. One is out of a jet ski the other from a snowmobile. Someone in 

Montreal built redrives for them. One a/c is due for completion in 2008 and 

the engine has started ground testing.

The idea of using the Rotax gearbox is good in terms of reducing the risk of 

using a combination of non aviation engine and newly designed redrive. In 

terms of gear ratio, I believe they plan to run the Yamahas at about the 

same RPM as the Rotax 912 (5800 to 6000). One limitation on the basic 701 

design to consider is 200 lbs and 100 HP max for the engine. As far as 

thrust loads on the engine and the mount I would also recommend including 

gyroscopic loads generated by the engine, redrive and prop.

My brother, a snowmobile enthusiast, told me these engines have a good 

reputation and Yamaha has released a three cylinder version that may even be 

lighter and could also be a good match for the 701.

Carl/701/912



---

special4

Joined: 27 Sep 2006
Posts: 28

Posted: Fri Dec 28, 2007 9:02 am Post subject: Re: Trying an unproven engine - is it feasible, is it safe?

Hi Randy,



I like your idea of the fuel injected yamaha....but as with all conversions it might be a lot of work/time. As for the reduction drive... I would not go with a Rotax as I think the power output of the yamaha is to high. As the prices for the Rotax/Jabiru/Continental and Lycomings are "sky high" (and climbing), I am planning to use a conversion engine...



Peter 

601XL

do not archive

_________________
Sportsflyer

paulrod36(at)msn.com
Guest

Posted: Fri Dec 28, 2007 12:30 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]-->  Every "firster" who ever tried a new non-aircraft component asked the same  question--"is it feasible, is it safe?" If not for the "firsters", we'd still be  using nothing but Lyconentals, and wishing somebody would come up with something  different, and cheaper. It's both feasible and safe , when you figure out  how to make it so. That's what experimental arcraft is all about. Take a good  look at the engine. Find somebody who can show you the guts of the redrive.  Figure out what it will take to join the two units. Figure out how strong it  will have to be. You'll probably have to build one to determine if there are any  harmonic issues you need to deal with. And on, and on. Then you'll need to  figure out exactly where, in relation to the fire wall, it needs to be, for  weight and balance purposes. Then, figure out what kind, and size, of prop it  works best with. And, after having figured out a thousand ways it didn't work,  you'll either give up, or have developed one sweet FWF that people will salivate  over, and pound down your door to get either the plans, the parts, or the whole  thing from you. Do it or not? Your decision. That's experimental aviation. On a  smaller scale, we all do a little something outside of the box, be it different  bracing, different turnbuckles, different fuel tanks, etc. Personally, I'd go  for it, and see what happens. At worst, you'll make junk out of an engine and  redrive, and waste some money at the machine shop.

  

 Paul Rodriguez

 [quote]   ---

Joemotis(at)aol.com
Guest

Posted: Fri Dec 28, 2007 1:02 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

top rated recipes and easy ways to stay in shape for winter.

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Joemotis(at)aol.com
Guest

Posted: Fri Dec 28, 2007 2:04 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

Excuse    me     list?!?!

  

 Joe Motis

  

 Do not archive



See AOL's top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

lrm(at)skyhawg.com
Guest

Posted: Fri Dec 28, 2007 7:51 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

Well said.  If is wasn't for people like "some of  us"  we would be rolling rocks and picking our rears.  Just test, test  and test again and when you think you got it right, test it again.  On the  ground, that is.  LRM, www.skyhawg.com

 [quote]   ---

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Sat Dec 29, 2007 10:04 am Post subject: Re: Trying an unproven engine - is it feasible, is it safe?

Let's look at two statements the original poster made.



1."I am not an engineer, or even a pilot yet, but I do enjoy building, fabricating, working with metal, etc. "



2."Would I be better off going with a more proven conversion like the Suzuki/Geo or go with the 912?"



Statement 1 pretty much stands on it's own. There is no mention that he has ANY experience with aircraft mechanics. He's not even a pilot.



Statement 2 seems to show that he is just trying to come up with an aircraft he can fly. I will be anyone here $100 that should the original poster ever try to build a 701 or any plane with the engine he described it will never get off the ground.



I'm hardly against conversion engines. But those that go about designing such conversions need to either have at least some experience with aircraft power plants or a real strong background in engineering.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

Joemotis(at)aol.com
Guest

Posted: Sat Dec 29, 2007 11:07 am Post subject: Trying an unproven engine - is it feasible, is it safe?

In a message dated 12/29/2007 10:06:04 A.M. Pacific Standard Time,  wr.giacona(at)suddenlink.net writes:

  	  Quote: 	
		  http://forums.matronics.com 	
 But those that go about designing such conversions need to either have at  least some experience with aircraft power plants or a real strong background in  engineering.

  

 I    disagree,    trial  and     error    teaches     many things. And     it     would    be    great    to  see     this    150     HP  in     an aircraft.   Quite a  lot    is    already     known    about     conversions     and     heck,     a    redrive     is    the    same      thing    in    principle    as  the     jackshaft   I     installed    on    a Bonaza    mini    bike toaccomadate    the     Hodaka    Ace    90     that   was     replacing    the  Mac   9.

 This    Yamaha  4      stroke    seems to    me     a     good    place  to  start      if    one  was     so       inclined.     

  

 Many    a      failed  attempt      at something     quite    often    turns      out    be   quite an      educational    experience.

  

 Joe  Motis

 Do not archive

 

  

  

  

  

  

  

 http://i83.photobucket.com/albums/j311/jdmotis/Genesis150_tcm26-67175.jpg



top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

AB_Summit

Joined: 16 Jul 2007
Posts: 23

Posted: Sat Dec 29, 2007 11:45 am Post subject: Re: Trying an unproven engine - is it feasible, is it safe?

 	  Gig Giacona wrote: 	
		  Let's look at two statements the original poster made.



1."I am not an engineer, or even a pilot yet, but I do enjoy building, fabricating, working with metal, etc. "



2."Would I be better off going with a more proven conversion like the Suzuki/Geo or go with the 912?"



Statement 1 pretty much stands on it's own. There is no mention that he has ANY experience with aircraft mechanics. He's not even a pilot.



Statement 2 seems to show that he is just trying to come up with an aircraft he can fly. I will be anyone here $100 that should the original poster ever try to build a 701 or any plane with the engine he described it will never get off the ground.



I'm hardly against conversion engines. But those that go about designing such conversions need to either have at least some experience with aircraft power plants or a real strong background in engineering. 	




You're right, I don't have any experience with aircraft mechanics and I am not a pilot, and my goal is to get an aircraft I can fly.



I also agree that on my own I would not be capable of building a flying aircraft, however with the help of people who DO have experience with aircraft mechanics and engineering and by joining the EAA and RAA and leaning on the experience of members in those organizations I think it is possible.



I also agree that the combination of a new pilot, new airframe and an unproven engine/redrive combination probably isn't wise, and that's something I'll need to consider as well, for now I'm just asking questions and learning.



I do know from the number of emails that I have received off list that there is considerable interest in using these engines in aircraft. So far I know of four projects that are in progress using this engine or the smaller 3 cylinder version, and one of them is currently using the 912 and intends to change to a Yamaha snowmobile engine. So the idea doesn't seem to be a bad one.



As I said, with my level of experience, this may not be a smart way for me to go, but I think this engine has great potential and it seems that there are others who agree with me.

ter_turn(at)yahoo.com
Guest

Posted: Sat Dec 29, 2007 12:05 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

The golden years of experimental aviation reached it's peak (probably in the sixties and seventies) and went into a steep decline, which is now reflected in the false illusion that safety is achievable only by using factory built parts.I wasn't a builder then, but you can imagine a lone figure toiling in his garage on a project, with no Internet, no builder forums, few  good reference books, but a lot of ingenuity and  common sense. Those days are long gone.  Many pilots will just shell out the ninety grand for a factory built sport plane and leave the building to the few true experimenters who love to create. There's nothing wrong with that approach but don't try to stifle the enthusiasm of the guy who wants to try to build his own dream with limited resources but a lot of heart.



When many in my fathers generation dreamed of home ownership they bought a piece of land, and took shovel to dirt and started building. Now we're told you have to have an  Architecual drawing, soil analysis by a professional and a certified landscape company to plant your grass, and whatever you do, don't try to do your own interior decorating, the paint fumes may explode!



This afternoon we should all tip our glass to the guys that went before and flew that creation with the model "A" engine sputtering while spinning that homemade wood prop!



Terry Turnquist

601 XL Plans

St. Peters, MO

 

Joemotis(at)aol.com wrote:[quote]     In a message dated 12/29/2007 10:06:04 A.M. Pacific Standard Time,  wr.giacona(at)suddenlink.net writes:

  	  Quote: 	
		  http://forums.matronics.com 	
 But those that go about designing such conversions need to either have at  least some experience with aircraft power plants or a real strong background in  engineering.

  

 I    disagree,    trial  and     error    teaches     many things. And     it     would    be    great    to  see     this    150     HP  in     an aircraft.   Quite a  lot    is    already     known    about     conversions     and      heck,     a    redrive     is    the    same      thing    in    principle    as  the     jackshaft   I     installed    on    a Bonaza    mini    bike toaccomadate    the     Hodaka    Ace    90     that   was     replacing    the  Mac   9.

 This    Yamaha  4      stroke    seems to    me     a     good    place  to  start      if    one  was     so       inclined.      

  

 Many    a      failed  attempt      at something     quite    often    turns      out    be   quite an      educational    experience.

  

 Joe  Motis

 Do not archive

 

  

  

  

  

  

  

 http://i83.photobucket.com/albums/j311/jdmotis/Genesis150_tcm26-67175.jpg



top rated recipes and

Joemotis(at)aol.com
Guest

Posted: Sat Dec 29, 2007 12:09 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

Any links to     the people  experimenting  with these engines?

  

 Joe Motis

  

 Do not    archive



top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

rblassett(at)alltel.net
Guest

Posted: Sat Dec 29, 2007 1:02 pm Post subject: Trying an unproven engine - is it feasible, is it safe?

Very  well said Terry.  Nobody wants to see anyone get hurt but it is very  admirable to "experiment" in my humble opinion.

  

 Russ

 [quote]   --

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