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deck angle

 
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taildrags



Joined: 29 Dec 2009
Posts: 1606
Location: Medford, OR

PostPosted: Thu Sep 28, 2017 7:51 pm    Post subject: deck angle Reply with quote

I thought I'd change the subject line to reflect the actual topic of discussion here ;o)

I just reviewed the plans (Orrin Hoopman's 1-19-33 plans, Drawing No. 1) and it calls for 2 degrees of incidence on the wing, achieved by making the rear cabane struts 1" shorter than the front ones. The cabanes on my airplane are not built per plans, but after studying their actual geometry in AutoCAD, when my cabanes are canted back by 3-1/2" from the vertical as they are, my wing incidence is within 1/2 of a degree of what it's supposed to be, or about 1.5 degrees. I can probably get that half-degree back after changing out my main gear tires to the 8.00x6s as I'm planning to do.

Now to the broader topic of the deck angle. It has been said by several Piet pilots that they feel like a deck angle of 12.5 degrees is about right. With another 2 degrees of incidence built into the wing, that puts the AOA of the wing in the 3-point landing configuration at about 14.5 degrees. I took the liberty of snipping a small section from Michael Shuck's very interesting paper called "Commentary On The Pietenpol Airfoil", copyright 2004 by Michael, full credit and admiration is here given to Mike for both being a Piet lover and for having tremendous skill in the analysis of airfoils. That snip is attached. Highlighted in yellow is the region of interest, which is the region where the coefficient of lift Cl reaches its maximum... the critical AOA. The first column on the left is alpha, the angle of attack. The second column is the coefficient of lift. Notice that Cl is at its maximum at an alpha of around 14 degrees, and it drops off at higher angles of attack.

Hmmm... sounds like the seat-of-the-pants Piet pilots know just as much as the aerodynamicists! My conclusion here is that if a Pietenpol airfoil is operated at a deck angle of 12.5 degrees in the landing configuration, it is just about at the critical AOA and if the airspeed is dropping, the wing will be stalling. Perfect. I don't consciously try to land my airplane tailwheel-first because I generally find that that will cause porpoising to start, but theoretically it would land nearer to full-stall if I held the nose a bit higher than I normally do at touchdown.

I'm very interested to do some flight testing in calm morning air with the bigger tires. They are on their way here from Colorado Springs as we speak...


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Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop
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bickersKEVIN



Joined: 30 Sep 2017
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PostPosted: Sat Sep 30, 2017 2:30 pm    Post subject: Re: deck angle Reply with quote

Howdy Oscar,

I love a good discussion about a/c configuration, but beware of deck angle vs angle-of-incidence! Angle-of-incidence is referenced from wing chord line to the top longeron, while deck angle is ground-plane referenced to top longeron. So a bigger tire will indeed increase your deck angle, allowing a greater angle-of-attack (alpha) during t/o and landing but it will not change the angle-of-incidence. You are absolutely right about wanting to get as close to possible to the critical alpha during this phase for the slowest possible forward velocity. Think of landing gear geometry (including tire size) controlling deck angle and the cabane struts controlling angle-of-incidence. The ideal configuration would give (deck angle + angle-of-incidence) = (critical alpha), while keeping the angle-of-incidence at Mr. Pietenpol's recommended values.

The Piet seems to allow for some wiggle room in rigging but your missing 0.5deg of wing angle-of-incidence (i_W) would theoretically reduce the full-up pitch authority of your tail assuming the horizontal stab angle-of-incidence (i_H) is rigged to plans at 0deg to top longeron. Honestly, I think a lot of these small control characteristics are lost in the noise when comparing Piets, due to the vast number of areas for small differences in each build!

YMMV, but in my experience a tailwheel first landing actually decreases the chance of a porpoise when compared to a mains first touchdown. It is essentially the same principle as a tricycle a/c, where in our case the CG is forward of the tailwheel but aft of the mains. Inertia in the tailwheel first landing will cause the mains to 'plop' down while decreasing alpha, reducing lift and the possibility of said porpoise. On the other hand, in a mains first landing the CG aft of the ground contact point will continue downwards, increasing alpha (and lift). This scenerio is described nicely in "The Compleat Taildragger Pilot" by Harvey Plourde, where he calls the porpoise a 'jounce' (And I know that's not how complete is spelled but that's actually the title of the book!).

Regardless, I bet you will like your new tires! Hopefully you can do some comparison testing in nice calm conditions to see if there is any appreciable change in t/o and landing speed.


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taildrags



Joined: 29 Dec 2009
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Location: Medford, OR

PostPosted: Sat Sep 30, 2017 6:55 pm    Post subject: Re: deck angle Reply with quote

Kevin; my kinda guy... numbers, angles, all that stuff ;o) Believe me, I read and re-read what I wrote so as to be as clear as I could be about the angles, relative wind, angle of incidence, and all the rest of it. What I did *not* bring into the discussion was laziness. Yes, I know I could rework the cabanes to restore the angle of incidence that is called for in the original design but it's fussy work for someone who is not a welder nor set up for metal working. I know a superb welder and he could do it for me. However, as I posted earlier, seeing the in-flight photos of my airplane from the eclipse weekend flight, I didn't like the proportion of the tires to the rest of the airplane and I was already thinking about going to a bit larger and plumper tires. Once I got to studying the deck angle and wing incidence, it occurred to me that going to taller tires would put the nose higher in the three-point attitude and that might help me land with the wing nearer to critical AOA. The lazy man's work-around for adjusting for a shortage of wing incidence ;o)

At touchdown in the three-point attitude the deck angle is the angle while sitting static on the ground, so at that instant the AOA if the airplane is neither climbing nor descending should be = deck angle + wing angle of incidence and should be = critical AOA if that's the target (and it is, in this case). That's my story and I'm sticking to it!


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Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop
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bickersKEVIN



Joined: 30 Sep 2017
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PostPosted: Sat Sep 30, 2017 7:06 pm    Post subject: Re: deck angle Reply with quote

Hopefully those news tires help! What size are currently on your plane? And I didn't mean to imply that your cabanes need any fixin' cause that's defintely no short order! I also meant to ask, do you have a full CAD model of your Piet??

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taildrags



Joined: 29 Dec 2009
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PostPosted: Sat Sep 30, 2017 7:08 pm    Post subject: Re: deck angle Reply with quote

Whoa. Back up the truck just a little bit there, Kevin! You wrote something very interesting when you said that a little less wing angle of incidence might reduce the full-up pitch authority of the tail assuming that the horizontal stabilizer is rigged at 0 degrees (mounted flat onto the top longeron), which mine is. In fact, I find that I can't really power-off stall the airplane to a noticeable break unless I almost whip-stall it, which would seem to bear out what you're saying. I have plenty of room to bring the stick all the way aft (others have mentioned that being 'profound round' means you might not be able to get the stick all the way aft), but even so all I get is mushing and nodding... never a true stall break.

Interesting observation! Maybe the next improvement to 41CC will be having my welder friend Jeff Sterling correct the cabane geometry. I've been threatening to have him rework the main gear leg upper pivots on the airplane anyway, because they have always had just a bit of slop due to the holes being ever-so-slightly larger than the bolts, and I haven't wanted to ream them out to move up a bolt size for fear of thinning the metal too much at the pivot/attach points. Taxiing on rough ground, my gear makes a definite soft clunking as the gear leg pivots bounce around on the bolts.


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Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
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PostPosted: Sat Sep 30, 2017 7:21 pm    Post subject: Re: deck angle Reply with quote

That lack of a true stall may just be a nicely behaved plane! In our Pacer I have a similar situation where it never really breaks (just kind of a constant descent rate mush) unless it's heavy and I really force a stall. Every Piet is different but during the initial stall series testing in ours, I got very little break, enough for a falling leaf maneuver (sounds like your mushing and nodding), but nothing as sharp as say a Citabria (which is not really much of a stall either!).

My comment about full elevator authority stems from the wing-to-horizontal relative angle. According to your numbers earlier, you have about 1.5deg instead of 2deg relative. This could be solved by giving the horizontal stab -0.5deg angle-of-incidence (i_H), but then you would have a non-standard body axis. Sooo it would probably be better to rework the wing cabanes or just accept that your Piet has some nice gentle stall characteristics Smile


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taildrags



Joined: 29 Dec 2009
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PostPosted: Sun Oct 01, 2017 2:54 pm    Post subject: Re: deck angle Reply with quote

Kevin; I'll take what you said on the positive side: the airplane has very mild stall characteristics!

Regarding tires, right now I've got 6.00x6 Desser Aero Trainer tires on the airplane. The ones I've got coming are Condor 8.00x6s.

And as to your last question, I don't have the complete Air Camper in .dwg CAD format but I do have some of the basic elements such as the side view framing, the wing rib, and some landing gear (mains and t/w) set to the geometry of my airplane. I use these for studying various things, like what I'm doing now.


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Oscar Zuniga
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Air Camper NX41CC "Scout"
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oldbird



Joined: 23 Apr 2015
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PostPosted: Mon Oct 02, 2017 6:27 pm    Post subject: Re: deck angle Reply with quote

I am building my Air Camper from CAD drawings. Although slightly different from the original, they may help.

Semih Oksay
Istanbul, Turkey
C90 engine


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taildrags



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PostPosted: Fri Oct 06, 2017 7:31 am    Post subject: Re: deck angle Reply with quote

Just got the Condor tires. No time to mount them right now, but here are a couple of pix of how the 8.00x6s look next to the 6.00x6s. I've got the weights of both new and existing tires and tubes and will look at what effect it might have on W&B, but other than bumping up the empty weight a bit, it shouldn't change much. I'm keen to fly them to see how she lands with a bit steeper deck angle.

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Oscar Zuniga
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Ray Krause



Joined: 09 Oct 2013
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PostPosted: Fri Oct 06, 2017 7:49 pm    Post subject: deck angle Reply with quote

Oscar,

The larger tires certainly look better! But be aware the you will be going a LOT slower with all that additional drag! Maybe you could fill them with water (as in tractor tires) to get some extra weight up front....but you're not tail heavy?

Ray Krause
SkyScout coming along s-l-o-w-l-y!

Sent from my iPad

Quote:
On Oct 6, 2017, at 8:31 AM, taildrags <taildrags(at)hotmail.com> wrote:



Just got the Condor tires. No time to mount them right now, but here are a couple of pix of how the 8.00x6s look next to the 6.00x6s. I've got the weights of both new and existing tires and tubes and will look at what effect it might have on W&B, but other than bumping up the empty weight a bit, it shouldn't change much. I'm keen to fly them to see how she lands with a bit steeper deck angle.

--------
Oscar Zuniga
Medford, OR
Air Camper NX41CC &quot;Scout&quot;
A75 power, 72x36 Culver prop




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taildrags



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PostPosted: Sat Oct 07, 2017 8:26 am    Post subject: deck angle Reply with quote

Ray; I can't imagine that the larger tires will make that big a difference in cruise airspeed, especially since my throttle is typically only set about 60% open in cruise. I run my A75 more like an A65 and the fuel burn reflects that conservative power setting. I have the power available to overcome the additional drag.

My empty CG is at roughly 13" aft of datum (wing L.E.) and the main gear axles are at about 6.8" aft of datum, so heavier tires will move the CG forward by just a tad. I'll know more once I weigh the new tires and tubes compared to the old ones.


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PostPosted: Sat Oct 07, 2017 9:02 am    Post subject: deck angle Reply with quote

Oscar, it is unseemly to brag about the high performance of your 75 hp monster.vs the morning pedestrian A65.

Seriously, is there much difference?
On Oct 7, 2017 11:27 AM, "taildrags" <taildrags(at)hotmail.com (taildrags(at)hotmail.com)> wrote:
Quote:
--> Pietenpol-List message posted by: "taildrags" <taildrags(at)hotmail.com (taildrags(at)hotmail.com)>

Ray; I can't imagine that the larger tires will make that big a difference in cruise airspeed, especially since my throttle is typically only set about 60% open in cruise.  I run my A75 more like an A65 and the fuel burn reflects that conservative power setting.  I have the power available to overcome the additional drag.

My empty CG is at roughly 13" aft of datum (wing L.E.) and the main gear axles are at about 6.8" aft of datum, so heavier tires will move the CG forward by just a tad.  I'll know more once I weigh the new tires and tubes compared to the old ones.

--------
Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop




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br> enpol-List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Pietenpol-List
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eferrer" target="_blank">http://forums.matronics.com
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errer" target="_blank">http://wiki.matronics.com
====================================
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====================================





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Ray Krause



Joined: 09 Oct 2013
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PostPosted: Sat Oct 07, 2017 12:09 pm    Post subject: deck angle Reply with quote

Oscar,
I'm sure you will see no difference In your plane's performance or W/B. I knew you had it all figured out.....as our resident aeronautical engineer! I really appreciate all you writings and calculations regarding all things Pietenpol.
Thanks for everything,
Ray Krause

Sent from my iPad

On Oct 7, 2017, at 10:01 AM, Steven Dortch <steven.d.dortch(at)gmail.com (steven.d.dortch(at)gmail.com)> wrote:
Quote:
Oscar, it is unseemly to brag about the high performance of your 75 hp monster.vs the morning pedestrian A65.

Seriously, is there much difference?
On Oct 7, 2017 11:27 AM, "taildrags" <taildrags(at)hotmail.com (taildrags(at)hotmail.com)> wrote:
Quote:
--> Pietenpol-List message posted by: "taildrags" <taildrags(at)hotmail.com (taildrags(at)hotmail.com)>

Ray; I can't imagine that the larger tires will make that big a difference in cruise airspeed, especially since my throttle is typically only set about 60% open in cruise. I run my A75 more like an A65 and the fuel burn reflects that conservative power setting. I have the power available to overcome the additional drag.

My empty CG is at roughly 13" aft of datum (wing L.E.) and the main gear axles are at about 6.8" aft of datum, so heavier tires will move the CG forward by just a tad. I'll know more once I weigh the new tires and tubes compared to the old ones.

--------
Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop




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taildrags



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PostPosted: Sat Oct 07, 2017 1:23 pm    Post subject: Re: deck angle Reply with quote

Steve; the A75 is basically just an A65 that has some modifications that provide adidtional lubrication and cooling when the engine is run at higher RPM to put out more power. The engines have the same bore, stroke, and compression ratio. The A65 makes its rated power at 2300 RPM and the A75 makes its rated power by turning up past that to 2600.

Both my A65 and A75 run the Stromberg NAS3-A1 carb with 1-1/4" venturi and #49 main jet. When I was flying with the A65, I never had the throttle firewalled in cruise either... there was virtually no difference in cruise speed by pushing the throttle in our out that last about 15% so I ran it where it felt right, which was 2200-2250. I run the A75 about 2400. Prop selection is what lets the A75 wind up to a higher RPM than the A65.


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PostPosted: Sat Oct 07, 2017 1:54 pm    Post subject: deck angle Reply with quote

Is climb much better? Load hauling?

On Oct 7, 2017 4:25 PM, "taildrags" <taildrags(at)hotmail.com (taildrags(at)hotmail.com)> wrote:
Quote:
--> Pietenpol-List message posted by: "taildrags" <taildrags(at)hotmail.com (taildrags(at)hotmail.com)>

Steve; the A75 is basically just an A65 that has some modifications that provide adidtional lubrication and cooling when the engine is run at higher RPM to put out more power.  The engines have the same bore, stroke, and compression ratio.  The A65 makes its rated power at 2300 RPM and the A75 makes its rated power by turning up past that to 2600.

Both my A65 and A75 run the Stromberg NAS3-A1 carb with 1-1/4" venturi and #49 main jet.  When I was flying with the A65, I never had the throttle firewalled in cruise either... there was virtually no difference in cruise speed by pushing the throttle in our out that last about 15% so I ran it where it felt right, which was 2200-2250.  I run the A75 about 2400.  Prop selection is what lets the A75 wind up to a higher RPM than the A65.

--------
Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop




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taildrags



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PostPosted: Sat Oct 07, 2017 7:03 pm    Post subject: Re: deck angle Reply with quote

Steve; this is Aero 101: there are four basic forces that act on an airplane in flight: gravity, lift, thrust, and drag. We can't change gravity, so that leaves us three variables. Of those three, drag is pretty much a characteristic of our airframe and accessories, but we really don't see a lot of streamlined Air Campers so drag is going to be proportional to velocity. Most Air Campers all cruise in a pretty narrow range of airspeeds, so we can almost treat drag as a constant too. Yes, we can use fairings to reduce intersection drag where struts meet the fuselage and wings, and we can install wheel pants to reduce drag from the landing gear and maybe do a little better than a stock airplane. The rest of it is parasite drag from the wing, plus drag from the brace wires and the "flat plate" surface area that the airplane presents to the oncoming air. Bottom line, we can't do too much about drag.

That leaves two variables: lift and thrust. The Pietenpol airfoil is pretty efficient at producing lift and it's got a lot of surface area, so it can lift quite a bit of weight at a good rate of climb if you can keep the air moving over it at a good airspeed. Thrust is what it takes to overcome drag, which increases airspeed, which increases lift, which overcomes gravity. So thrust is king, and it's horsepower that produces thrust, so that's our big variable.

The basic powerplant for the Air Camper is a nominal 40HP Ford engine (some say 35HP, so we'll say somewhere in that range but 40 is a nice round number). With that amount of power, the Air Camper can get two people off the ground with the airplane at max gross, but it's not going to climb very well. The Ford A engine has enough excess thrust to overcome the airplane's drag, which keeps the air moving over the wing at a decent rate, which creates enough lift to get the airplane and its load off the ground and climbing, which overcomes gravity. So let's develop a very theoretical situation where we have a 2500 ft long runway with a fully-loaded Ford A-powered Air Camper taking off at one end. If it takes off, climbs out, and flies a rectangular traffic pattern that puts it at traffic pattern altitude of 900 AGL by the time it's abeam the numbers for power reduction for landing, it will have flown maybe 8000 ft through the air at 50 MPH, so let's round it off and say the airplane may have taken 2 minutes to climb the 900 ft to pattern altitude, for a climb rate of 450 ft/min.

The next most common engine in the Air Camper is the A65, which provides (on paper, at least) about 60% more horsepower than the Ford. Since the Ford is quite capable of doing the job of lifting a fully-loaded Air Camper off the ground, a lot of the A65's 25 additional horsepower is available to develop excess thrust, which provides a better rate of climb with a full load. It won't increase the climb rate by 60% to 720 ft/min, but let's just say it does. That means the airplane could climb to pattern altitude in 1.25 minutes, putting it at pattern altitude when it gets abeam the numbers at the departure end of the runway (more or less), rather than when abeam the numbers at the approach end. Just talking hypothetically now, but when I used to fly that kind of a square pattern flying out of San Geronimo, I may have been able to achieve that on a good day.

My A75 can produce maybe 80% more power than the Ford, so a lot of its 35 additional horsepower is available to develop excess thrust to provide a better rate of climb with a full load. Playing the same theoretical game as with the A65, let's say the climb rate on my airplane is now 810 ft/min and I can maintain it all the way to pattern altitude if I fly the airplane at 50MPH. I should be able to get to pattern altitude in just a little over a minute, which means I would be at pattern altitude as I turn onto the downwind leg from crosswind. Pretty optimistic, I may have seen that kind of performance on one or two cold mornings when everything was perfect, but stay with me now for the rest.

The O-200 and the Corvair can each produce about 100HP... about 150% more power than the Ford. If I use the same ratio of rates of climb, that would mean that a Corvair or O-200 powered Air Camper could make a climb rate of 1125 ft/min in the same scenario and I should be at pattern altitude in 48 seconds, which would put me at pattern altitude just before I turn onto the crosswind leg on takeoff. I would have to ask the PietVair pilots out there whether their airplanes can take off from a 2500 ft strip, climb out at 50 MPH at full gross, and be at pattern altitude before turning crosswind after leaving the runway departure end threshold about 1000 feet behind them, but my guess is that they might.

On a hot day at anything higher than sea level and with little or no headwind, all of those theoretical numbers are going to sag like a beer belly, and I've only created these scenarios to provide food for thought.


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PostPosted: Sat Oct 07, 2017 7:42 pm    Post subject: deck angle Reply with quote

So Oscar, you really don't know! Ducking and running.

Your discussion makes sense. My experience is with Cessna 150s vs 152s. The 150 has a 100 hp Continental vs the 152 with a 110 hp Lycoming. But I never could tell a difference in performance.
My other experience is shopping for a Piper Tripacer. The 135hp model was a marginal 3 placer that doesn't climb well. The 150 hp model flies really well and hauls 4 people. The 160hp  is great.
On Oct 7, 2017 10:05 PM, "taildrags" <taildrags(at)hotmail.com (taildrags(at)hotmail.com)> wrote:
Quote:
--> Pietenpol-List message posted by: "taildrags" <taildrags(at)hotmail.com (taildrags(at)hotmail.com)>

Steve; this is Aero 101: there are four basic forces that act on an airplane in flight: gravity, lift, thrust, and drag.  We can't change gravity, so that leaves us three variables.  Of those three, drag is pretty much a characteristic of our airframe and accessories, but we really don't see a lot of streamlined Air Campers so drag is going to be proportional to velocity.  Most Air Campers all cruise in a pretty narrow range of airspeeds, so we can almost treat drag as a constant too.  Yes, we can use fairings to reduce intersection drag where struts meet the fuselage and wings, and we can install wheel pants to reduce drag from the landing gear and maybe do a little better than a stock airplane.  The rest of it is parasite drag from the wing, plus drag from the brace wires and the "flat plate" surface area that the airplane presents to the oncoming air.  Bottom line, we can't do too much about drag.

That leaves two variables: lift and thrust.  The Pietenpol airfoil is pretty efficient at producing lift and it's got a lot of surface area, so it can lift quite a bit of weight at a good rate of climb if you can keep the air moving over it at a good airspeed.  Thrust is what it takes to overcome drag, which increases airspeed, which increases lift, which overcomes gravity.  So thrust is king, and it's horsepower that produces thrust, so that's our big variable.

The basic powerplant for the Air Camper is a nominal 40HP Ford engine (some say 35HP, so we'll say somewhere in that range but 40 is a nice round number).  With that amount of power, the Air Camper can get two people off the ground with the airplane at max gross, but it's not going to climb very well.  The Ford A engine has enough excess thrust to overcome the airplane's drag, which keeps the air moving over the wing at a decent rate, which creates enough lift to get the airplane and its load off the ground and climbing, which overcomes gravity.  So let's develop a very theoretical situation where we have a 2500 ft long runway with a fully-loaded Ford A-powered Air Camper taking off at one end.  If it takes off, climbs out, and flies a rectangular traffic pattern that puts it at traffic pattern altitude of 900 AGL by the time it's abeam the numbers for power reduction for landing, it will have flown maybe 8000 ft through the air at 50 MPH, so let's round it off and say the a!
 irplane may have taken 2 minutes to climb the 900 ft to pattern altitude, for a climb rate of 450 ft/min.

The next most common engine in the Air Camper is the A65, which provides (on paper, at least) about 60% more horsepower than the Ford.  Since the Ford is quite capable of doing the job of lifting a fully-loaded Air Camper off the ground,  a lot of the A65's 25 additional horsepower is available to develop excess thrust, which provides a better rate of climb with a full load.  It won't increase the climb rate by 60% to 720 ft/min, but let's just say it does.  That means the airplane could climb to pattern altitude in 1.25 minutes, putting it at pattern altitude when it gets abeam the numbers at the departure end of the runway (more or less), rather than when abeam the numbers at the approach end.  Just talking hypothetically now, but when I used to fly that kind of a square pattern flying out of San Geronimo, I may have been able to achieve that on a good day.

My A75 can produce maybe 80% more power than the Ford, so a lot of its 35 additional horsepower is available to develop excess thrust to provide a better rate of climb with a full load.  Playing the same theoretical game as with the A65, let's say the climb rate on my airplane is now 810 ft/min and I can maintain it all the way to pattern altitude if I fly the airplane at 50MPH.  I should be able to get to pattern altitude in just a little over a minute, which means I would be at pattern altitude as I turn onto the downwind leg from crosswind.  Pretty optimistic, I may have seen that kind of performance on one or two cold mornings when everything was perfect, but stay with me now for the rest.

The O-200 and the Corvair can each produce about 100HP... about 150% more power than the Ford.  If I use the same ratio of rates of climb, that would mean that a Corvair or O-200 powered Air Camper could make a climb rate of 1125 ft/min in the same scenario and I should be at pattern altitude in 48 seconds, which would put me at pattern altitude just before I turn onto the crosswind leg on takeoff.  I would have to ask the PietVair pilots out there whether their airplanes can take off from a 2500 ft strip, climb out at 50 MPH at full gross, and be at pattern altitude before turning crosswind after leaving the runway departure end threshold about 1000 feet behind them, but my guess is that they might.

On a hot day at anything higher than sea level and with little or no headwind, all of those theoretical numbers are going to sag like a beer belly, and I've only created these scenarios to provide food for thought.

--------
Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop




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