Transwing UAV

[okikuma]

Transwing UAV from PteroDynamics Inc.

Wayne

 

[Resasi]

Looks very interesting. 1 up of a tilt wing.... this one both tilts and folds.

 

[Aerofoam]

There is a rush for the VTOL stuff and this is typical of over engineered molded carbon airplanes that are consuming huge amounts
of tax dollars to do missions that a simple plane could perform and could be built for 5% of the cost of the complex molded aircraft.
The expensive plane will self destruct before it wears out, so there is no point in building it with the most expensive techniques and
hundreds of individually molded parts, when it could be almost a tooless built design with vacuum bagged foam and composite.
Unfortunately these half million dollar aircraft are getting funding and the absurdity keeps growing.....
The VTOLS suffer from carrying all that extra weight and hardware for the VTOL portion of the flight, there is a definite need for some VTOLS
but not most of the time, especially when the flight time is so compromised by the extra weight and drag....

 

[okikuma]

One has to remember the DoD pays a contractor $10,000.00 for a toilet seat cover that a 3D printer could print for $300.00

The Ukrainians and Hamas have shown very effective reconnaissance and anti-personnel ordnance delivery with simple off-the-shelf "throw away" sUAS.

Wayne

 

[Aerofoam]

One has to remember the DoD pays a contractor $10,000.00 for a toilet seat cover that a 3D printer could print for $300.00

The Ukrainians and Hamas have shown very effective reconnaissance and anti-personnel ordnance delivery with simple off-the-shelf "throw away" sUAS.

Wayne

Unfortunately, I have direct experience with designing and prototyping one of these under the idea that I was cloning an enemy
loitering munition so they could learn how to shoot it down.
The company I was working through dealing with a big 5 letter DOD agency promptly stole my design and had made
hundreds of them that are being lobbed into other country/ies as we type.
There was a provision for them going around me, I only wanted 2%, but they stiffed me on that one too...
I can't really take legal action because the father of one of the players controls the purse strings for a major DOD player
and I would probably be black listed....
BTW, they are throw away munitions, but we are probably paying over $300k per unit for something that
should be about $10k.

About the 10K toilet seats, that is usually laundering $$ for black projects.

 

[okikuma]

Unfortunately, I have direct experience with designing and prototyping one of these under the idea that I was cloning an enemy
loitering munition so they could learn how to shoot it down.
The company I was working through dealing with a big 5 letter DOD agency promptly stole my design and had made
hundreds of them that are being lobbed into other country/ies as we type.
There was a provision for them going around me, I only wanted 2%, but they stiffed me on that one too...
I can't really take legal action because the father of one of the players controls the purse strings for a major DOD player
and I would probably be black listed....
BTW, they are throw away munitions, but we are probably paying over $300k per unit for something that
should be about $10k.

About the 10K toilet seats, that is usually laundering $$ for black projects.

Unfortunately, welcome to the world of DoD contracting and conducting business.

I once worked for a large Aerospace company back in the 1980's and early 1990's. One day, I walked into a conference room to look at the scheduling chart to see when I could use the room for a presentation a couple weeks ahead. On the conference table, there were boxes filled with #10 business envelopes addressed to several political candidate donation centers of both major political parties (it was an election year). The returned address on the envelopes were names and addresses of "ordinary citizens" from all around the country. Obviously, this was done to get around the maximum dollar amount that a company can contribute to a political candidate as set by law. I asked a couple of friends of mine that worked "inside the Beltway" about this. They told me that this is not a secret and is "standard operational procedure" with every large company in the Nation. The largest donor receives the contracts.

Wayne

 

[Aerofoam]

I had a group of retired brass who wrote an SBIR that was aimed at me because we already had stage 1 and 2 development and could immediately
go into production. It should have been a shoe in, but it got diverted to 2 separate local companies with better political connections.
Neither one ever delivered and we had working aircraft in the hanger.....

 

[okikuma]

I agree with you Mark. There are plenty of simple RC aircraft designs that are easily adaptable as inexpensive sUAS.

The 1930s Free Flight Quaker design.

SIG Kadet

Even the the simpler Das Ugly Stik

With any of the three, one can remove the single engine and mount the camera at that location on the nose. Add nacelles to the wing for twin electric motors.

Any 2m or 3m RC glider with a power pod could be used as an effective sUAS

Mark, have you seen the Bearospace Industries Gemini V-2 sUAS? Spike Webb is the founder of the company sells plans for those who desire to build their own. One can also purchase from Bearospace Industries a complete custom built example.

Wayne

 

[Aerofoam]

There are some things I like about that, but what stands out is too many build difficulties.
*Polyhedral wing makes construction more difficult, higher parts count.
*Twin engine is less efficient (sometimes necessary though)
*Landing gear, I avoid it, extra weight, extra drag.
*Built up balsa wing, friends don't let friends build stick built aircraft,
I could build a hot wired "Hershey Bar" wing from foam with a spar and laminating film covering in about 3 hours.
*Overall parts count is very high, lots of little things that need assembling, I treat these aircraft as minimum effective dose...
*Lots of cludgy stuff hanging out in the air stream......

This one below can carry a 35lb. payload for 36 hours on 2.6 gallons of gas and we have flown it in monsoons with 45mph. gusting winds.
I can build one of these by myself in a week. They have been flown at up to 125lbs GTOW.
But normally are about 60lbs.

 

[okikuma]

Remember, one does not need to build a Quaker, Kadet, or Ugly Stik out of balsa wood. As you mentioned, hot wire foam reduces the parts count. Polyhedral wing designs were the primary method of roll stability before micro-electronic stabilization.

Spike is a modeler that has grown into sUAS developer. His niche market are small commercial sUAS operators that are RC modelers as well. Not big commercial or government / DoD programs. Just like there are people who enjoy building and flying full size EAB aircraft, there are modelers that enjoy the build as well.

Wayne

 

[okikuma]

Flying wing designs are aerodynamically very efficient aircraft. The Almighty knew this when he designed his avian creatures as all flying wing designs.

Fineartamerica.com

We all know about Dr. Alexander Lippisch 1930’s study and designs of flying wing (tailless) aircraft.

Me 163 prototype

In the 1940’s, 50’s and 60’s, gentlemen such as Charles Fauvel, Al Backstorm, and Jim Marske developed a series of flying wing gliders for the same reasons of efficiency, and ease of construction.

https://www.nurflugel.com/Nurflugel/Fauvel/e_backstrom.htm

https://www.nurflugel.com/Nurflugel/Fauvel/e_machines.htm

https://www.nurflugel.com/Nurflugel/Fauvel/e_marske.htm

Fauvel FV.22

Al Backstrom EPB-1C Flying Plank

Model of Backstorm EPB-1C

Marske Pioneer 1A

Marske Pioneer II-D

Over the years, various RC modelers have constructed and flown various flying wing models as gliders and powered aircraft for their own education and enjoyment.

So it is no secret to design a sUAS on a proven flying wing design with readily available, inexpensive materials.

Thus the Sypaq Corvo Precision Payload Delivery System.

https://en.wikipedia.org/wiki/Sypaq_Corvo_Precision_Payload_Delivery_System

 

[Mayfield]

Or Don Mitchell's U-2, A-10, and B-10. I've flown all three and they are neat little aircraft.

I also built and flew a Mitchell P-38. Fun, but not nearly as elegant as his tailless aircraft.

Jim

 

[Aerofoam]

I basically was obsessed with flying wings to the point of heavily studying Horten's designs and writings and early Northrop designs.
The Hortens were light years ahead of everyone to the point of incorporating the Prandtl lift distribution curve in the early 30's
I was building flying wings based on Hortens research in the mid 90s, over 10 years before Bowers rediscovered the Prandtl formulas.
Of course I didn't know about the bell shaped lift distribution curve, but I was building aircraft with it based on Horten designs.
My delta wing series was what caught the attention of some people at Sandia and got my foot in the DOD door.
I also had a discus launched micro flying wing called the Noseeum. It had a 31" span weighed 5oz. all up and you could slope it off a row of parked cars. You could discus launch it to about 75' without too much effort.
Between the Delta wings and Noseeums, I sold about 2000 kits.
I actually sold about 9 of the big deltas before realizing how efficient they were and took them out of the civilian market....
At 14 lbs. they only consumed about 120w at 50kts cruise and with flexible solar panels they could generate almost twice the power they needed
for cruise.

 

[SSDriver]

I learned how to fly rc models with a Sig Kadet MK2.
Built it in about 2 weeks, flew it for a long time.
rebuilt it a few times as well, LOL Some of those landings were a "little" rough on it.

 

[Aerofoam]

There was a hobby shop in ABQ that did a lot of work for Sandia NL. and one of the guys
I worked with had them build a 24ft. wing span Telemaster Senior.
I saw it once in the trailer, but didn't see it fly. It apparently flew very well.
I am fairly sure it could have carried a person....

 

[Aerofoam]

This was an experimental wing that was loosely based on the Horten designs.
I think this was around 1998.
This wing thermalled well and was a rocket on the slope.The roll rate was rather slow despite the large elevons....
I dicovered later that the tiplets damp roll rate and create drag if they are located at about 1/3rd. span from center.
I flew this wing with no vertical surfaces quite a bit and although it did not have much adverse yaw, any yaw would
translate to a yaw occilation that did not want to return to center due to the span and lack of drag at the tips.
The one thing that Prandtl D does not address is that the large amount of washout that creates the bell shaped curve
essentially just becomes up elevator input on a flying wing and this is why they needed the CG much farther forward.
I am not entirely convinced that the lift distribution efficiency from minimizing tip vortexes will outweigh
the increased work load and drag from countering a nose heavy wing with upward deflection at the tips....
I sort of went the other direction and increased efficiency by moving the CG aft to the point of NOT needing
elevon input for level flight. This is touchy because it can create a pitch divergent aircraft with a very sensitive
pitch response if it isn't kept in check by other design elements.
Most of the tip altering designs end up sort of being "One Speed" answers that are only fully effective
at a specific speed range. I believe this is weighted towards higher Reynolds numbers and the small lightly loaded
aircraft can have a wider range of effectiveness...
I experienced this with tiplets, but have seen a negative effect with twist....
The devil is in the details and the answers are always somewhere in the middle of all the trade offs....
For recreational gliders, I ended up putting a vertical surface on a long carbon spar which not only was a yaw damper, but the long
arm also damped pitch too. This, massaging the airfoil a bit and a little more sweep, tamed the aft CG.