# A challenge to you all

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#### brehmel62

##### Well-Known Member
This thread has been going on for awhile but hasn't converged yet. It seems to me that the obvious starting point for an inexpensive, simple design is a primary glider.

Primary Glider Plans

This vehicle only weighs 150 lbs with a 32' wingspan and 157 sq ft of wing area. It has a 17:1 glide ratio. It's obviously wood and fabric with kingpost and cable bracing.

I like the idea of starting with a glider since any aircraft limited to ultralight specs (63 mph) isn't really that great for cross country anyway. If the weight stays low, you could probably use some type of RC engine to climb. With a longer wingspan and less drag, this vehicle might match an older sailplane like a Schweizer 1-26. And, even in my area in the Midwest, you can achieve bronze badges with a 1-26. I think an engine would be necessary because around me, they only have Pawnees for tugs and you can't tow an ultralight with one of these. Also, it would be nice to be able to fly even when there is no ultralight tug or an area of ridge lift. On grass, you could probably use a bungee and still be able to get airborne without a big engine.

Let's try some math. A Schweizer 1-26 has a 40' wingspan and a sink rate of 175 ft/min with a wing loading of 4.4 lbs / sq ft. So, with 700 lbs and a sink rate of 175 ft/min:
175 / 60 = 2.92 ft/sec
(700 lbs * 2.92 ft/sec) / 550 lb ft/sec = 3.7 HP for level flight
Climbing at, say, 400 ft/min would require:
(175 + 400) / 60 = 9.6 ft /sec
(700 lbs * 9.6 ft/sec) / 550 lb ft/sec = 12.2 HP. Allowing 80% prop efficiency = 15.2 HP for a 1-26.

Can we beat that? We could probably get a 40-44' wingspan if we used wing struts like on the Schweizer 2-33. That would also let us remove the kingpost and most of the cable bracing. Let's assume the same 175 ft/min sink rate and 400 ft/min climb rate. However, we should be able to keep the vehicle weight under 500 lbs (assuming 250 lb empty + pilot and fuel).
(500 lbs / 700 lbs) * 15.2 HP = 10.9 HP. We might be able to get that lower if could get the sink rate down or if we accepted something smaller like a climb rate of 300 ft/min. A Turnigy Rotomax 100cc brushless outrunner can put out 10.1 HP so we are close to an electric solution. Unfortunately, the obvious place to mount it would be behind the pilot where the pilot's seat would be blocking most of the airstream. We would either have to use a tapered fairing and airscoops behind the pilot's seat or perhaps use two motors on the wings. If we went to two motors, it would be easier to size them and their propellers. Of course, folding props would be essential. Electric would also be attractive in terms of not having to pull start them while flying. A couple of Turnigy Rotomax 50cc outrunners could put out 7 HP each. The weight is 1080 grams each.
I guess I need to figure the batteries to see if this is feasible.
We need a 12s battery for a maximum of 44 volts. However, we'll figure this as 37 volts. We need 120 amps to get 6 HP out of each motor. Looks like 3 minutes of takeoff and climb to reach a reasonable altitude to soar. Okay, so we know that we'll need 6 amp hours each or 12,000 milliamp hours total. We also know that we need at least 20C since it is three minutes.
Something like a Sky Lipo 4000mAh 40C 7.4 V is $25 and weighs 267 grams. 7.4 Volts is only 2S so we need 6 in series to reach 44 volts. This would give us 12S. Then we would need three in parallel to reach 12,000 mAh. 6 * 3 = 18. This would give us enough power to climb once. The weight would be 267 g * 6 * 3 = 4806 g. The motors are 1080 g apiece for 7 kg or 15.4 lbs total. That's about$450 for batteries and $385 for the two motors. These brushless motors require an Electronic Speed Controller to create 3-phase AC so another$105 for an ESC capable of 12S and 120 amps. And, then you need a servo tester to replace the receiver controller. That seems doable in terms of the power for climbing. One difficulty might be the propeller though. We can get a 30" x 8" propeller from JC Super Props (for about $76). A 32" would give us more thrust but I think 30" is about as much as we could handle in terms of tip speed. I also don't believe there is a folding hub available in this size. However, there are plans available for hinged autogyro hubs and these should be sufficiently robust. These brushless motors will run in either direction so we don't have to worry about the twist on the propeller although counter-rotating would be nice. Could we use a regular fuel Zenoah RC motor like the ZP 62cc? Maybe, but it wouldn't be easy. We can get one that puts out 6 HP. However, the good version requires a battery to drive the electronic ignition because the magneto version is hard to start and idles rough. Vibrations are bad so isolation mounts would be needed. And, if you plan to use a folding prop, you'll also need a flywheel and a clutch. The weight is now as high as the electric solution. The advantage though is that you can fly longer under power. However, endurance is not really that useful with a glider that only needs power to climb. I could see building a craft like this to go soaring. However, if someone was not interested in soaring then I can't see much advantage to the Part 103 ultralight spec. It would seem to be more logical to go all the way to Sport, shorten the wings, and pick up the cruise speed. You'd have something similar to the Starlite which was ultralight weight but faster. I guess I'll have to read through the whole thread now. #### stan40353 ##### Well-Known Member its been a rough road lol but i am ok, after i healed up i went to france and chilled.and as far as the accident.i was setting at a stop light.and a drunk tractor trailer driver slammed into me.thats all i wanna say about that, putting it behind me. now, i am going to focus on what i started. #### cluttonfred ##### Well-Known Member HBA Supporter Welcome back. "...went to France and chilled"...I do that too but then my wife is French, what's your excuse? I have actually started another thread trying to identify a small powered plane, I think it was a relatively recent German microlight, that essentially looked like a powered version of the glider above with with proper landing gear and a pusher engine. It's really bugging me that I can't remember where I saw it. Cheers, Matthew PS--The link in your signature does not seem to lead to anything. #### stan40353 ##### Well-Known Member my wife is french #### cluttonfred ##### Well-Known Member HBA Supporter Ahh, now it all comes together. ;-) #### stan40353 ##### Well-Known Member Winter is fast approaching, so I am going to start buying material,now that I am able to get back to work, still not exactly sure what direction I want to go in, but the question is, where can I find tubing that is 15 feet long at the best price? I have searched high and low in this town and we have nothing, thanks all #### stan40353 ##### Well-Known Member 40199 views on this thread. it sparked interest.and i am still determined to get to what my original post was all about.i have talked to so many people as a result.some have been people who have been in the industry for many many years.and some that have built craft from just an idea. i have came a very long way in my understanding from the first post in this thread. i thank each one of you. #### stan40353 ##### Well-Known Member designing the hba-103 on paper!! yes in 2 years i have educated myself! #### jbiplane ##### Well-Known Member Here's another engine, ready to bolt on for (guessing) in the region of$2000. I've sent them a pricing enquiry so will let you know.
Comes with 1:3.43 reduction gearbox - for an ideal airscrew speed of 2500rpm
Friend of mine got 3 different Chinese 2-cylinder engines from different companies.
After wrong experience he ask me produce 7 for UAVs.

Now I started small batch production of one carb version 294 cc engine with reed valve in numerous customer-driven configurations.
Most of the parts have German and Taiwan origin (Pvl.de or NCY ignition, Mahle cylinders, Japanese ore Ireland's carb)...

Weight 8.64...11.5kg (+alternator+ electrical starter +tuned pipe) Power 22-31hp (depend of exhaust system).
One of the first engines already tested for 170 hours. Crankcases and our important parts CNC milled. Details upon request.

jbiplane@gmail.com
Valeriy Rutkovskiy

#### Robert Dingus

##### Well-Known Member
Stan, was the goal of this original post for an aircraft that fits the ultralight 103 or the light sport area. im close to finishing my first build and am around 3500.00

#### jedi

##### Well-Known Member
Ref Post 749 - the engine is the key and it soounds as though you have a good start but the Russian / US sanctions thing may mess it up for us. Otherwise, the V twin industrial 4 stroke thing may work if weight is OK.

REf Post 750 - I think US UL part 103 regulations were intended and that would be my goal.

Ref Post 738 - This is tending to converge on a Pterodactyl Ultralight configuration. That is a very well liked design and could use some construction improvements. That would tend to make it more like an American Aircraft Falcon Ultralight but it was too intricate of structure, expensive and delicate.

I would suggest that what is needed here is a simple aluminum built up wing as opposed to the typiclal Ultralight leading edge / trailing edge tubular spar and ladder design. Norm has the capability to build such a wing and is looking for assistance and offering parts. I have seen and flown his work and think it has potential. Look into it. Norms flying Boat Started by Norm Langlois

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#### Peter Lee

##### Member
Here in France the best single-seat "ulm" ,the Luciole (M. Colomban) uses the B+S Vanguard 23hp . It weighs 100kg empty and has an excellent performance (200km/h). to get a reasonable performance and take-off , weight is the priority, so the construction is not for beginners. Unfortunately it costs, for even the best builders, €17,000!
I have done a lot of research and concluded that the lack of a really appropriate motor frustrates a lot of good projects in this category.

#### bmcj

##### Well-Known Member
HBA Supporter
Here in France the best single-seat "ulm" ,the Luciole (M. Colomban) uses the B+S Vanguard 23hp . It weighs 100kg empty and has an excellent performance (200km/h). to get a reasonable performance and take-off , weight is the priority, so the construction is not for beginners. Unfortunately it costs, for even the best builders, €17,000!
I have done a lot of research and concluded that the lack of a really appropriate motor frustrates a lot of good projects in this category.
The old Rutan Quickie offered an affordable build for engines in that power range.

#### Topaz

##### Super Moderator
Staff member
Log Member
The old Rutan Quickie offered an affordable build for engines in that power range.
And the Quickie could be substantially improved upon to produce even more "practical" performance, especially in climb, with such small engines. The aircraft was terribly span-limited, and I'm told high-density-altitude performance reflected that. Something like a Quickie, but of a more conventional layout and longer span, would probably be about as low as you can go and expect any kind of "practical" city-to-city utility.

If you just want to "go up and float around", then the design task becomes even easier until you artificially impose Part 103 constraints, at which point it gets to be much harder again.

#### nerobro

##### Well-Known Member
Log Member
And the Quickie could be substantially improved upon to produce even more "practical" performance, especially in climb, with such small engines. The aircraft was terribly span-limited, and I'm told high-density-altitude performance reflected that. Something like a Quickie, but of a more conventional layout and longer span, would probably be about as low as you can go and expect any kind of "practical" city-to-city utility.

If you just want to "go up and float around", then the design task becomes even easier until you artificially impose Part 103 constraints, at which point it gets to be much harder again.
There's something to be said about effectively not needing spars on a plane with a span that's so short. But then again, Burt put the landing gear out at the tips...

Now I kinda want to see one flying.

#### bmcj

##### Well-Known Member
HBA Supporter
Now I kinda want to see one flying.
They fly well. The only two shortcomings that come to mind is the less than desirable ground handling (the lightly loaded tailwheel skids sideways easily), and the low climb rate with the original Onan engine (I think I typically saw about 3-400 fpm).

#### wecycle

##### New Member
I think the Gene Turner design T-100D Mariah would fit the goals of the OP. (Adams Aeronautics Company, Inc) adamsaero.com
The engine I believe would provide the right power and weight combination would be a 2 cyl opposed 2 stroke 400cc with direct oil injection rather than premix and direct chamber fuel injection as the Evinrude Etec style.
This would be lightweight and fuel efficient. I may want to add flaps to get a semi STOL capability.
Dennis in West Richland, WA

#### choppergirl

##### Banned

I think I'm going to go with rockets on my ultralight... gasoline and electric are so passe... rockets though, make lots of smoke, turn heads and draw a crowd

Nobody cares to see a girl in a motor glider. Who's stopping what they are doing and going to the airport for that? Pfft, nobody. A rocket glider, on the other hand, now that's a different thing...

https://en.wikipedia.org/wiki/Opel_RAK.1

Even better if I take my cat along too... because, well, the internet loves cats...