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Airboat props and custom builds

Farmboy

MEMBER
Middlebury, VT
This is a good video. But big airboat paddles have been around for awhile, I’m surprised to have not heard about someone trying them for STOL work before.
Sensenich offers a good looking one for the 160-up hp O-320.

https://youtu.be/stkvTQ1lCSw
 
Watched that last night, he is my hero, energy, youth, money, and a passion for playing...Yee hawww
 
Byron Root and Dale Krugger were playing with O-540 and I0-720 on beefed up cubs 30 years ago with big 2 blade and 3 blade propellers. Not for the same reason though, they were interested in getting into hunting places and hauling a load. Very heavy cubs that would have landed like a lawn dart if you did not have power.

I don't see how it will work for playing side by side with a light weight carbon cub. Just the raw power of that engine harnessed to that propeller does not seem very practical when you see how much torque the air boat has. It will be interesting to see though, might just flip it over when you nail it. I can't see it being much fun to fly except to go straight up!
 
Byron Root and Dale Krugger were playing with O-540 and I0-720 on beefed up cubs 30 years ago with big 2 blade and 3 blade propellers. Not for the same reason though, they were interested in getting into hunting places and hauling a load. Very heavy cubs that would have landed like a lawn dart if you did not have power.

I don't see how it will work for playing side by side with a light weight carbon cub. Just the raw power of that engine harnessed to that propeller does not seem very practical when you see how much torque the air boat has. It will be interesting to see though, might just flip it over when you nail it. I can't see it being much fun to fly except to go straight up!

I predict he’ll prove you wrong.


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As an engineer, Patey continually amazes me. I don't know what his formal training background is but his knowledge and understanding is impressive. Cubic Bucks helps also. He earned every penny of it.
 
He is a self taught engineer, no formal engineering school. I am curious to see how this turns out. He is a smart cookie but from what I have seen over the years some of this stuff is PFM and no theory to support it. I am skeptical because of all this added weight. I have always been curious about what he comes up with for gear after talking to Mark at length at Sun & Fun about their projects.
 
It’s awesome that he is doing this, and with enough hp anything will fly. But will it fly well? The secret to a good flying cub is light weight.


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Take notice that he put wing extensions on Draco before he went to Valdez. Originally he seemed to believe that the center section wouldn't take the loads.
 
Luckily for us he has the money, time and motivation to create one-off concepts and mods, and if they don’t work he changes it until it does. Not many people can do that.
While formal training would help him build an aerospace company, I believe that by nature formal training also constrains one’s ability to think/dream/conceptualize the truly different ideas.
If builders and pilots can gain one small idea to use in the future from his work, it was well worth it.


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Mounting that engine looks a lot like what the deHavilland Canada engineers went through to mount the R-985 on the Beaver. Interesting adaptations.

MTV
 
Luckily for us he has the money, time and motivation to create one-off concepts and mods, and if they don’t work he changes it until it does. Not many people can do that.
While formal training would help him build an aerospace company, I believe that by nature formal training also constrains one’s ability to think/dream/conceptualize the truly different ideas.
If builders and pilots can gain one small idea to use in the future from his work, it was well worth it.


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And he documents it with great videos


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I flew the 5 place Sherpa with IO-720 and big 3 blade propeller. It flew slow, took off short lightly loaded but I would not want to fly it day in day out against a light weight nimble cub.
I never flew the 8 place Sherpa with the IO-720 but the concept was similar to the 5 place. The engineering on the Sherpa was hit and miss I think, they took cub like design and made it bigger.
The 5 place Sherpa had some quirks that made it less then user friendly, when you got it slow with full flaps it felt unstable. When you put the power to it on take off it was very pitch'y.
They then put a turbine engine with the same wing and fuselage that the 8 place had. I flew in that airplane (back seat) as Paul Claus test flew it and it was not right, in fact Paul was not impressed from what I remember, it was not safe according to Paul. Then a person decides he has to have one and Sherpa is more then happy to sell one to him. On the test flight the test pilot that has a lot of time in the IO-720 8 place almost wrecks it and refuses to fly it again. They then call a real test pilot (that is what he does for a living) and he almost bails out of it flying it from SPB to UAO where it is to undergo a complete make over. The engineer determine that the airplane is to short coupled and needs the fuselage stretch more then 4 feet but the guys hangar is not big enough to go more then 4 feet so that is what they decide to do (better then nothing). When you are building airplanes hangar size should not dictate engineering requirements. They also determine that the wing is to far forward by feet not inches and decide to change that also. The rudder and vertical are to small and the horizontals and elevator also I believe. They make all theses changes and the test pilot makes return trips to evaluate the stages of changes because they want to spend the least amount of money to make it airworthy so they do it in steps based on what the test pilot thinks is going to be most effective in making this airplane safe to fly. What I say here is just to illustrate that more needs to go into building an airplane then just bolting on a bigger engine with more HP, maybe Mike has done all the calculations to make this airplane right maybe it will be just PFM. Since he is sharing as he builds it, it is hard to see if there was serious thought about all that needs to happen to make an airplane work correctly.

I know nothing about Draco except for what I have seen and it is impressive but could anyone with say a lot of Turbine Otter time just hop into that airplane and fly it safely. Or is it an airplane that has quirks that would make it dangerous.

There is not a single thing about Draco that transfers over to the kind of Cub flying that I can afford and enjoy. It is a eye catching, money sucking show plane that only average mortals can only slobber over. All that being said I like his crazy ideas so keep them coming.

If he needs someone to prove that a guy with a lot of off airport time and a little turbine time can fly Draco just fine have him give me a call.
 
Wing loading, power loading, and balance. That's what makes them work. That much weight on the nose will be a challenge. Extending the fuselage aft isn't enough to solve the problem.
 
Amazing enthusiasm! Will be interesting to see the wing for this machine!
Mike Patey may just be getting close to doing what the the RC guys do- hover indefinitely.
 
If he needs someone to prove that a guy with a lot of off airport time and a little turbine time can fly Draco just fine have him give me a call.

I think you meant to say a lot of contrived off airport time for sport and the camera.

Besides, if you want to fly Draco so bad, you should call him.

Hats off to Mike Patey for his impeccable craftsmanship and follow-through!
 
I’d be very concerned about torque roll. An airboat would never have a problem, but read numerous reports from ww2 and see what a problem it was. I’d also like to be there for first good run up, I’m curious about the windscreen flexing with that kinda power. As for the Sherpa discussion, history teaches us about numerous designers making the mistake about designing airplanes around hangars ie the British Short Stirling
 
Good luck with this thing. Never heard the Sherpa didn't fly ok. Seems to me the compression side of the fusalage would be where the beefup would be needed. Wouldn't want to be on board and hit anything.
 
Wing loading, power loading, and balance. That's what makes them work. That much weight on the nose will be a challenge. Extending the fuselage aft isn't enough to solve the problem.
Have you not even noticed he moved all the engine weight back about 2' feet, he also moves the occupants back as well.
I have done the same thing on my build where I am going from a small Continental to a larger, longer and heavier Lycoming. The aft face of my engine is moved back almost 8" to make the plane balance out. The propeller will be the original distance from the wing LE.
 
I noticed his motor weighs nearly double mine, and my motor is moved back and the airframe is extended. It isn't enough. Just my experience. Y'all can reflect on your own experiences.
 
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Just eyeballing the fuselage, it looks to have a stock chord on the wing? Seems like a good opportunity to build a deeper chord wing to carry the load a little better, the aesthetics of it might take some work though.
 
If he needs someone to prove that a guy with a lot of off airport time and a little turbine time can fly Draco just fine have him give me a call.
Contrived or not he does not need to call me to fly the Scrappy Cub unless it is PFM. I think it is going to be a less than fun for contrived off airport flying.:lol:

I think you meant to say a lot of contrived off airport time for sport and the camera.

Besides, if you want to fly Draco so bad, you should call him.

I have never called anyone to fly an airplane and never will. Every airplane I have ever flown is because someone called me and wanted me to experience it. In most cases I was somewhat apprehensive as I don't consider myself a person with a lot of experience in different types of airplanes... That being said I moved out of my comfort zone for the experience because I figured I would never get a chance at affording my own airplane of that type. In every case when I got back into my own airplane it was a relief to be in something that felt natural again.

Greg
 
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. I think it is going to be a less than fun for contrivedbecause I figured I would never get a chance at affording my own airplane of that type. In every case when I got back into my own airplane it was a relief to be in something that felt natural again.

Greg


Done a bunch of first flights on my own scatter brained designs as well as a few for others. I have found that we all are obliviously more partial to what we spend our time in. Have always told folk who move to a new mount, Don’t make any decisions on it till you have at least 50 hours.
A lot of times, the things that you are obsessed about in the first few hours turn out to be no concern after you get use to it. Sometimes the quirks can be an advantage when you learn how to use it. In aerobatics, When you move to a new mount, Even if it’s of the same design, you are not effective with it usually till around 60 to 80 hours. It’s then you are feeling the wings lift in your hand and the rudder in your feet!
So it’s no surprise when a pilot spends on a few hours in a new mount that they always feel theirs is a better flyer.
On Pateys new design, With his history of past builds....My money is on it doing exactly what he’s designing it to do !
 
Couple things:
pretty sure Mark was the first to point out that this was a ridiculous idea.
Those that are comparing it to a traditional stol aircraft are missing the point.
I followed the videos of his Draco build with skepticism, it could have been a total flop but Mark had the courage to share his build and innovative ideas via well produced videos, with an unknown outcome. Draco is not for everyone, not intended to compete with other utility aircraft on the market. It is a collection of well thought out innovative ideas that should motivate and inspire others to think outside the box, and more power to him for fulfilling his dreams and sharing.
Im guessing his new build will share in the “success” as Draco when one defines the mission of the build.


Re comment on “contrived” backcountry experience:
My hats off to you Alaska guys that earn a living in the off airport environment, I am grateful for the wisdom and experience you guys bring to this forum.
However, most cub type aircraft are owned and flown as a form of recreation. There’s a sector of cub pilots that take it a bit further and find great satisfaction in pushing the limits on what a cub will do. “contrived” landings in places most wouldn’t think of.
Personally, I obsess over looking for new and challenging places to land. When driving a car thru the countryside I catch myself scheming an approach to an uphill, impossibly tight meadow, hell, I’ve planned in great detail the approach thru wires and around trees into a high school soccer field I pass on my commute to work.
I typically operate with 1/4 fuel and empty plane when out pushing the limit so l lack the experience and doubt I could do what some of you professional pilots can do with a loaded aircraft. Dosnt make me any less of a pilot though.
To each his own.
 
If you’re not aware, he has a couple recent videos up on YouTube for his carbon cub build.


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I like his carbon envelope idea, always thought if I made my own Jeep hardtop I would cover a frame with dacron then lay carbon on top. It would be shaped like a fabric top but be durable, quiet and warm.
 
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