Mark Stull - outside the box designer

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Gregory Perkins

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https://markstullcollection.shutterfly.com/

I dont know anything about his designs other than I was impressed by his creativity and thinking outside the box approaches to design etc and felt that
it would be a real waste if all his efforts and designs were forgotten l I am not even sure which of his designs he died in or what if anything he overlooked that caused his death or whether the design should have been adequate and there was a mechanical or material failure. We have seen a lot of prolific aviaition guys perish because of their haste and insistence on testing themselves where there could have been other ways to progressively test... maybe models or wind tunnels or swivel attachments to trucks or trailers etc.
One thing that I always thought technology could provide today and even back then would be the use of remote control of a full size model that was fully loaded and that could be tested to destruction without the need for risk to human life. More than 20 years ago I attended an RC model plane fly-in and there were several full size planes that were using adequately large servos and motors to control the full size planes. Sadly, all that equipment is probably too expensive for the average back yard designer.
There were dozens of creative geniuses from around the world that were involved with ULs and it is too bad many are already lost and forgotten.
I have been searching for ideal hosting sites that would allow organized archival of all the significant UL planes and I have not been able to really find a good solution. For the time being the SHUTTERFLY site is useful for individual album topics
 

radfordc

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More than 20 years ago I attended an RC model plane fly-in and there were several full size planes that were using adequately large servos and motors to control the full size planes. Sadly, all that equipment is probably too expensive for the average back yard designer.
Hmmm... I would like to know more about this. I've been intimately involved with RC modeling for over 50 years and have yet to see a full size plane controlled by RC equipment outside of military drones such as the Predator, etc. Today there are some very large models that approach full size dimensions, but not all the way to 1:1 scale.
 
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BJC

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One thing that I always thought technology could provide today and even back then would be the use of remote control of a full size model that was fully loaded and that could be tested to destruction without the need for risk to human life.
Wasn’t there a recent thread here about that?


BJC
 

RonL

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This is not an airplane, but might be a good place to start, when it comes to the size of servos and large scale electronics.

 

Dana

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Mark died in his last design, which combined a hang glider wing (which needs no tail) with a motor and a conventional tail. It wasn't controllable from the moment it left the ground. In retrospect it seems obvious that it was a bad idea, he may have been lulled into a false sense of security by his previous successes. R.I.P.

There has been discussion of remote control of full size prototypes here before. The hardware isn't the issue. Pops may chime in here, he built an autopilot for his plane using large R/C servos which worked well, but he later removed it, saying, "why should the autopilot have all the fun?"

The problem with full scale testing via R/C, as I see it, lies in not the size pe se. but with the way they fly. Piloting an R/C model (without autopilot or artifical stability augmentation like the multicopter drones have) is generally acknowledged to be more difficult than flying a full scale airplane. You don't have instruments, you don't have control feel, and you have to visualize the plane as it would look if you were in the cockpit even though you're standing on the ground. However, you're helped by the fact that R/C models are (usually) insanely overpowered by full scale standards, and incredibly strong-- I know of a guy who put a g-meter in an R/C pylon racer and it recorded 27 g! So the all-too common rough landing that puts the model on its back is no big deal.

Now take a full scale plane with all the things that make R/C more difficult, and you don't have the extreme amount of excess power to pull out of a stall or other bad situation, you don't have the durability to make a bad landing a non event, and you've got to get it back down on a runway that's proportionally much narrower than a typical R/C field.

Nobody wants to go through all the work of building a full size airplane and then "testing it to destruction", either.
 

Riggerrob

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R/C magazines often show models approaching 20 feet (7 metres) in wing span.
What is the longest wing-span of an amateur-built R/C model airplane?
What is the heaviest amateur-built R/C airplane?
Weights are not mentioned, but I am guessing half that of a similar-sized, manned airplane.
What are the torque or tension limits on current-production R/C servoes?

I often wonder why R/C model-builders don't devote the same amount of labour and materials to building a Hummel Bird.

There was a recent article (Kitplanes Magazine?) about a competition sailplane that was re-winged and the new wing used R/C servos to control ailerons. Hard-wiring servos to the joy stick eliminates one level of complexity.

Another option is "hacking" into an existing auto-pilot.

Modern cameras make it easy for the ground-control pilot to see things from the same perspective as a flesh-and-blood pilot. Perhaps even add extra cameras to confirm landing gear retraction or control surface deflection.
If hairy-chested test-pilots consider this a wimpy approach, then limit R/C to the most dangerous tests like: First, flutter and spin with aft C. of G.

Back to the OP's question: why not test-fly homebuilt prototypes with R/C?
 

TFF

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Mark was a integral part of this site. He was a true experimenter. He would show and discuss his projects. He hashed out the crucible tail plane on these electrons. I believe a lot of us did not like the configuration of his last design. No one thought we would find out the outcome the way we did.

Making everything big RC is not really a great idea on multiple levels. If you are not part of the RC world, join in its fun. After spending a summer or two, you would probably not want to commit a full size plane to RC. Not without big commercial equipment, government size test range and the shrug off of loosing it on the first takeoff. As my mom told me when I started RC, if it crashes you can’t cry about it. It happens. And a lot more than big airplanes. Add to the technical, the new government stance in drones. Five years a go it would have been a hold my beer moment. Now it’s a national security problem. That will probably destroy the tradition RC in time anyway.

Mark would not have flown his plane RC. He was a junky on flying new ultralights. If he could not experience that thrill, he would have picked up another hobby.
 

radfordc

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R/C magazines often show models approaching 20 feet (7 metres) in wing span.
What is the longest wing-span of an amateur-built R/C model airplane?
What is the heaviest amateur-built R/C airplane?
Weights are not mentioned, but I am guessing half that of a similar-sized, manned airplane.
What are the torque or tension limits on current-production R/C servoes?

I often wonder why R/C model-builders don't devote the same amount of labour and materials to building a Hummel Bird.
One of the biggest heaviest RC planes was this B-29 model at 29 feet span and 400 lbs.


Big RC servos produced up to 8 ft/lb of torque. HS-1005SGT Giant Scale Digital Industrial Metal Gear Servo | HorizonHobby

People who build big RC planes get as much satisfaction as people who build Hummel Bird's. Not everyone wants to be a "real" pilot.
 

lr27

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If the risk to the airframe is twice as much, but the risk to the pilot is 0.1 percent, I think RC test flying would be a good deal. Modern RC sensors and telemetry are inexpensive. Obviously you'd want to do this out in the middle of nowhere instead of at a normal airport. Also, you'd want to put more care and redundancy into the RC gear than you would for a model. The RC pilot must be an expert. Whether the FAA would ever allow it is another issue.

A guy I know used to test cargo parachutes for, I think, the Army. He would drop tbem f
rom a radio controlled, full scale ultralight. That was many years ago.

Please pardon the gratuitous, empty table interrupting my post. It's some whim of my phone and I can't seem to delete it.
 

BJC

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Please pardon the gratuitous, empty table interrupting my post. It's some whim of my phone and I can't seem to delete it.
The results of automation .....

Probly would never happen, never happen, never happen,

on an RC flight test.

BJC
 
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