# P-51C at ~70% scale as ultralight?

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#### Tangoavenger

##### Member

Totally off topic, but I think a standoff scale Mitsubishi A5M perhaps with a 3 cylinder radial, would be a nifty project.

Getting down to pt103 weight is a challenge, Period.

The Shetland Pony plane is great! Cartoon vs. Authenticity? Give me cartoon. I really really like it. Inspirational.

Someone already suggested a silhouette scale model approach without the weight of an enclosed fuselage. Tube & gusset, fabric covered. The Ultracruiser long wing is proven, and you can paint the Mustang taper on or better yet, faux paint where you just suggest it's tapered. For example, white tapered paint on leading and trailing edge, and polished in the Mustang wing outline shaped area. That eliminates the actual root leading edge extension for the retractable gear you don't have, but keeps the look. Paint the bombs on the underside, etc. ....

re: medical & licences.

If you've never Failed a Class 3 medical exam, then you can self certify for a Light Sport licence if you have a valid driver's license and just don't brag about your problems. Ethically, & personally, both of us are mortal, doomed, and "might" have a medical condition that might cause us to fail a Class 3. Ethically, if either of us... Any of us, thinks we might be a danger to others, for example a condition that causes unexpected blackouts, then we shouldn't fly, or drive a car, which is far more likely to harm others. Other conditions that might cause us to fail a Class 3, like Heart Disease or Diabetes, require personal, individual, judgment calls.

My OPINION is that if, for example, your condition is controlled, so you are unlikely to pass out, go comatose unexpectedly, then go have fun. You might die of a Heart Attack? Lots of people will. With no warning. So ask yourself, is that a possibility? Or a certainty? ( don't respond with answers! These are semi-rhetorical questions to ask yourself ) My call is to stay within my Real physical limitations. Not feared ones.

I spent a few years on blood thinners, and the prescribing Doctor warned about bruising and bleeding issues. He didn't want me to continue doing full contact martial arts. ( SCA armored historical combat ) That made sense. He also didn't want me to ride a motorcycle, or bicycle. I might fall down! That is excessive caution IMHO, YMMV.

I don't need to know your medical history. Use your own informed judgment. You may be just fine flying Light Sport where your medical history isn't anyone 's business, unless you crash.

keep on dreaming.
Was messing around for a couple minutes with your idea of Mustang shaped outline on Hummel wings. Looks promising, thanks!

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#### cluttonfred

##### Well-Known Member
Hehe, that’s neat. Should you paint the faux outline green or earth on top and sky blue on the bottom? ;-)

#### Tangoavenger

##### Member
3-way comparison:
Ultracruiser
shortened 65% P-51 caricature
65% P-51

Now, the caricature I've been trying to work at, to cut weight, has the same wing and tailplane as the 65% scale P-51, both of which have significantly greater tailplane area than the Ultracruiser.
I have a deposit on a Hummelbird, which is only 46 pounds over FAR103 with an 86 pound VW engine, so I'm thinking about an engine swap and going ultralight. I've been toying with some paint ideas and thought of you:

##### Well-Known Member
Log Member
I have a deposit on a Hummelbird, which is only 46 pounds over FAR103 with an 86 pound VW engine, so I'm thinking about an engine swap and going ultralight.
A Hummelbird will not make Part 103 for a few reasons.......ask me how I know.
1. Too heavy
2. Too fast
3. Stalls too fast
4. Fuel.....you can work around that.

There are other Hummel designs that will meet Part 103......but not the Hummelbird.
Been there and gave up on that after a few years and many different components & engines later.

Kevin

#### Tangoavenger

##### Member
A Hummelbird will not make Part 103 for a few reasons.......ask me how I know.
1. Too heavy
2. Too fast
3. Stalls too fast
4. Fuel.....you can work around that.

There are other Hummel designs that will meet Part 103......but not the Hummelbird.
Been there and gave up on that after a few years and many different components & engines later.

Kevin
Thank you Kevin. I was thinking I would swap in Ultracruiser wings, maybe redo just the fuselage skins in lighter aluminum like the ultracruiser, and with a 30lb 2 stroke engine (ZDZ500), I think I'd be okay, but it's a lot of work/changes

#### Bigshu

##### Well-Known Member
Thank you Kevin. I was thinking I would swap in Ultracruiser wings, maybe redo just the fuselage skins in lighter aluminum like the ultracruiser, and with a 30lb 2 stroke engine (ZDZ500), I think I'd be okay, but it's a lot of work/changes
I mentioned a similar idea to Terry Hallett, but with H5 getting lightened up. He said that there are enough changes that his suggestion was just pick up UC plans. Discount for repeat customer?

#### Tiger Tim

##### Well-Known Member
Using the Hummel Ultracruiser as a start, would it be feasible to leave the lion’s share of the wing alone but make tapered ailerons/flaps? That way the spars and ribs stay unchanged (and un-tapered for simplicity) but the wing planform is a little more Mustang-y than the Hummel’s Hershey bar wing.

#### karmarepair

##### Well-Known Member
Using the Hummel Ultracruiser as a start, would it be feasible to leave the lion’s share of the wing alone but make tapered ailerons/flaps? That way the spars and ribs stay unchanged (and un-tapered for simplicity) but the wing planform is a little more Mustang-y than the Hummel’s Hershey bar wing.
Your reward will be TERRIBLE aileron response. You want you ailerons big at the wingtips, to maximize their moment arm on the roll axis.

The Thatcher CX-4 tapers the ailerons like this, and the Only Fair aileron effectiveness is one of the few complaints about this airframe.

#### Riggerrob

##### Well-Known Member
Colin Thatcher designed CX wings for his favorite style of flying: docile. Since he wanted to make the airplane easy to fly - for low-time pilots - so Colin designed for a slow roll rate.
Pilot reports also concur that CX-4 is one of the most docile tail-draggers.
In conclusion, Thatcher's CX-4, -6 and -7 series do exactly what they are designed to do.

#### Marc W

##### Well-Known Member
The Thatcher CX-4 tapers the ailerons like this, and the Only Fair aileron effectiveness is one of the few complaints about this airframe.
The "Only Fair" aileron response is not because the ailerons are tapered. It is because the inboard end of the aileron matches the airfoil contour, which is fine as far as it goes. However on the shortened outboard end of the aileron, the top surface follows the line of the airfoil contour and the bottom surface is angled upward, away from the airfoil contour. This is a recipe for flow separation on the bottom of the aileron. When deflected downward, the outboard end of the aileron is ineffective as it travels through the dead air behind the rear spar until it reaches clean air along the bottom line of the wing.

I fixed that problem on my CX4. I made new ailerons with a longer chord. I made the outboard end of the aileron to fit the airfoil contour and lengthened the chord of the inner end of the aileron. My ailerons are crisp and light. Instant response!

The Thatcher roll response has nothing to do with the taper. It has everything to do with the detail design of the taper.

Colin Thatcher
is really Dave Thatcher.

Edited to add that I also made my new ailerons thicker than the wing at the rear spar to try to keep the flow attached. Something worked because they work great!

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#### J.L. Frusha

##### Well-Known Member
I haven't forgotten this thread/dream. Life takes turns and, well, now I'm buying a homestead. (30 year noose around my neck, with an anchor on the other end...).

When I can get more than 2 plug nickels to rub together, I'll be building a glider, which may become a powered ultralight.

Still been working with the P-51 C and have squeezed it down considerably. In RC speak, it's a 'Stand-off Scale' contraption, but the idea IS consolidating...

#### Victor Bravo

##### Well-Known Member
JLF, paint some nose art on the glider, airbrush some "panel lines" like the R/C Scale Masters guys do, paint the forward 12 inches of the nose bright yellow, and carry around a little digital audio recorder of a Merlin at full trot.

Get in the air sooner, rather than later, please trust me on that. My EAA chapter has taken in several airplane projects where "poor old Uncle Bubba died before he could finish his dream".

#### J.L. Frusha

##### Well-Known Member
@Victor Bravo

'Glider' and 'in the air, sooner' are the current priority beyond the farming. Gotta be solvent to pay for stuff.

At least, if the glider fails, half can be kindling and the rest can cover holes in the roof of one of the sheds.

"You've GOT to have a sense of humor... Look around you!" - Robin Williams (from: Reality What A Concept)

#### J.L. Frusha

##### Well-Known Member
Trust me, nobody is as aware of my mortality as I am...

I've survived 4 Strokes which damned-near put me in an institution for Dementia.
Now I have a faulty heart valve (told 'em the replacement needs to be stainless... I'll buy a Football-Jersey #01 and the 'name' will be "TIMEX"... Takes A Lickin' & Keeps On Tickin'
Broken Collar-bone from a motorcycle wreck (At least the dog I missed walked away...)
They called me 'Scar Face' in Basic at Ft. Knox (1984), from wearing facial scars after my head going through a windshield.
PTSD still hasn't whipped my @$$and isn't going to. When I die, it should be on my terms, not some random act of 'God', or Man. #### AeroER ##### Well-Known Member If you're retired, watch the recent Dennis Brooks videos on YouTube to learn how quickly you could build an Ultra Cruiser from the prefab'd kit, especially if you aren't flying as often as he does. You'll need to root around for the first video in this series. Also, ditch the NLF airfoil. You'll find nothing but detriment without a dead smooth wing to at least the spar, trim drag, and building complication. Way back in the 80's a local man had a Windwagon kit and drawings for sale, "bought while temporarily insane". That is still good for a chuckle. Last edited: #### J.L. Frusha ##### Well-Known Member If you're retired, watch the recent Dennis Brooks videos on YouTube to learn how quickly you could build an Ultra Cruiser from the prefab'd kit, especially if you aren't flying as often as he does. Way back in the 80's a local man had a Windwagon kit and drawings for sale, "bought while temporarily insane". That is still good for a chuckle. Can't afford their kit, for one thing. 100% VA Disability doesn't pay all that well, when covering a mortgage and a truck payment. If he still has the plans, I'd appreciate a copy. I have a digital copy and they're not all that well drawn. I also have plans for the all-metal Zipster Biplane, too. #### AeroER ##### Well-Known Member Can't afford their kit, for one thing. 100% VA Disability doesn't pay all that well, when covering a mortgage and a truck payment. If he still has the plans, I'd appreciate a copy. I have a digital copy and they're not all that well drawn. I also have plans for the all-metal Zipster Biplane, too. That ad occurred in the late 80's or close to 1990. I think I have an incomplete set of plans unless my brother took them back. I'll look around, but don't get in a hurry. The Windwagon plans are crude and for someone that knows how to build an airplane. #### J.L. Frusha ##### Well-Known Member I think I have an incomplete set of plans unless my brother took them back. I'll look around, but don't get in a hurry. The Windwagon plans are crude and for someone that knows how to build an airplane. Thank you. I appreciate the help. What I have is only 7 pages long, scanned into a pdf. I think I could use hem, but I'm not certain just how complete 7 pages is. I'll drop you a message with them. If it looks correct to you, then they will do. Wasn't sure you weren't talking about yourself in the third-person, what with the sarcastic remark from the ad. I do it pretty regularly... ("Some [email protected]$$ forgot to refill his prescriptions ontime", etc.,...).

Been a long while, but I do know some sheet-metal work, if not aircraft construction, itself. I used to work for Air Cargo, when they had a shop in Tulsa, Oklahoma. We (my shift) built the very first cargo boxes for the 747. Big ~8-10 ft cube with a wall in the middle and a fold-down shelf at about 3 ft above the floor.

As for the airfoil,in and amongst I have stuff for that foil with an L.E. Slat and T.E. Slotted Flaps, if my memory serves me well.

First things first, to flesh-out my glider plans, build it, then get some glider time in a log book.

#### AeroER

##### Well-Known Member
I believe the copy you sent is better than what I have. There might be some full size patterns in mine, but I'm not certain.

Now I'm curious about the glider you want to build. They're just lots of fun, especially in any kind of workable lift.

Sometimes I think a simple primary glider on auto tow would be fun. The trouble is, they're also lots of work to build like everything else. A couple of men in Belleville Illinois built a replica BG-8 glider in the 80's that was neat, but the cockpit isn't large enough for full size pilots. The BG-8 looks a lot like a sawed off SGU 2-22, but I don't recall the tapered wings on the BG.

#### J.L. Frusha

##### Well-Known Member
Been playing with P-51 stuff and could do a scale-ish Air Bike...