# Looks like a Mustang?

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#### Pops

##### Well-Known Member
Log Member
When I was a kid living out in the woods with my grandfather the AG at Charleston, WV just got the P-51's after the war. On Sundays there would be a string of 51's coming from the south and making passes on a knoll about 1 mile north. Good airshow every nice Sunday. Still in love with P-51's
On my first job out of high school my boss was a Flying Tiger and then flew P-51's in the war. We always ate lunch together and he would tell me his war stories.

#### C Michael Hoover

##### Active Member
"We always ate lunch together and he would tell me his war stories. " Pops, You are very fortunate to have heard those first hand.

cmh

#### don january

##### Well-Known Member
Log Member
what a sweat heart and such great lines. Good job all.

#### Lendo

##### Well-Known Member
Did someone ask what the Airfoil is?
TIA
George

#### TXFlyGuy

##### Well-Known Member
Did someone ask what the Airfoil is?
TIA
George
Yes. Separate thread. Turns out this is a very nice airfoil, based on the analysis of an aeronautical engineer friend of mine.

It does not hit a "brick wall", or speed-brake, as does the standard wing.

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#### TXFlyGuy

##### Well-Known Member
Did someone ask what the Airfoil is?
TIA
George
This from my aeronautical engineer buddy:

The airfoil on your wing, from what I see, has a reflexed UPPER surface toward the TE. The 6-Series are early attempts at controlled pressure recovery on the upper surface, and are more noted for having under-camber toward the TE so as to drive more camber aft into the TE of the section. I've certainly not seen them ALL, but this doesn't appear to be a NACA 6 series shape.

Nor does it resemble Riblett - from what I did study of his work (mostly in the "GA" series he did) they look very close to 6-series. Harry did seem to improve on the 6-Series, though - he never was regarded as a true "professional" aerodynamicist by those who do work in an aero-science capacity either for the Govm't or some major airframer.

The section I see here resembles more of some of the work Richard Eppler did, in some of his "low reynolds number" airfoil applications. Attempting to maintain laminar flow well back in the section with max thickness and camber pretty far aft.

#### pantdino

##### Active Member
Robert at KAXS (SW Oklahoma) is building one - waiting til next year to buy the firewall forward engine (Did he say $30 grand or was it$40 G? A stupendous number anyway. Think its a Subaru conversion. The fuselage controls and electricals are about complete and made like only a manufacturer's field rep can
The current FWF is a GM LS3 430 or 480HP with the standard PSRU and 84" prop or a 480HP with a 90" prop and bigger PSRU.

#### Twister51

##### Member
I commend you for all your hard work. Seriously. Your T-51 is waaaay closer to the real thing than when Titan began selling these kits. However....

The vertical stab lines are still wrong, the cockpit position in relation to the overall length of the fuselage is off (cockpit is slightly too far aft), the gear doors are too 'square-ish'. Love your big prop and the longer wing. I hope you have a lot of fun with this!

(BTW, the S-51 has inner gear doors. The prototype did not at first, then they were installed but were removed because they were problematic. An S-51 builder designed new parts and new computer logic to sequence them correctly.) Cheers!

#### TXFlyGuy

##### Well-Known Member
I commend you for all your hard work. Seriously. Your T-51 is waaaay closer to the real thing than when Titan began selling these kits. However....

The vertical stab lines are still wrong, the cockpit position in relation to the overall length of the fuselage is off (cockpit is slightly too far aft), the gear doors are too 'square-ish'. Love your big prop and the longer wing. I hope you have a lot of fun with this!

(BTW, the S-51 has inner gear doors. The prototype did not at first, then they were installed but were removed because they were problematic. An S-51 builder designed new parts and new computer logic to sequence them correctly.) Cheers!
You are correct on your observations. The Titan gear doors are backwards, totally incorrect. We addressed that as best as we could. Note our doors are quite close to the P-51H model.

The tail section was designed larger than scale to make the aircraft better for x-wind flying.

Not sure about the cockpit location...I’ll post a few more photos soon. I think it is where it’s supposed to be. But our nose is about 4 inches longer with the heavy duty PSRU.

We really like the long wing and big prop. Looks much better, and should be the best performing T-51 to date.

#### Pops

##### Well-Known Member
Log Member
"We always ate lunch together and he would tell me his war stories. " Pops, You are very fortunate to have heard those first hand.

cmh
And the stories were before PC.

#### BrianW

##### Active Member
The current FWF is a GM LS3 430 or 480HP with the standard PSRU and 84" prop or a 480HP with a 90" prop and bigger PSRU.
Yes indeed! A variety of engines have been fitted: Rotax, BMW, Honda, GM Corvette, etc.

#### TXFlyGuy

##### Well-Known Member
This one has the GM LS376-495, GM factory Hot Cam. 525 hp on the dyno, but we will only use 412 hp.

#### Twister51

##### Member
@ TXFlyGuy - If you added 4" to the nose for your PSRU then that is the difference. Hope you fly soon!

#### TXFlyGuy

##### Well-Known Member
@ TXFlyGuy - If you added 4" to the nose for your PSRU then that is the difference. Hope you fly soon!
Yes, the new prop hub and HD Gearbox added 4 inches to the nose. Requiring a new nosebowl and spinner design.

#### TXFlyGuy

##### Well-Known Member
And another item...the canopy is just slightly larger than true 3/4 scale. Problem is, there are no 3/4 scale pilots, so it was enlarged just a bit.

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#### Lendo

##### Well-Known Member
TX Can you say what the Airfoil is or is it specially designed IP.
George

#### TXFlyGuy

##### Well-Known Member
TX Can you say what the Airfoil is or is it specially designed IP.
George
Riblett 35-215 airfoil. Slightly modified like a 2.5-15.

But...here is some info from a real aeronautical engineer, who I flew with at United:

You've probably heard the terms "laminar" and "turbulent" in how they relate to what type of airfoil is on a wing. In the real world, every flow field starts out laminar and will "transition" to turbulent at some point along the wing chord, downstream of the leading edge. In some instances, aerodynamicists try to design wings with extensive laminar runs along the chord to reduce drag. But they're fighting a tough battle with surface roughness, skin seams, rivets, dirt and bugs. Cirrus did a particularly good job at that on the SR20 and SR22.

What having a higher Reynolds Number means to a pilot is that it helps to make the transition points on the wing more stable, and more predictable. This means less of a chance the "bottom will fall out" on your wing, less sensitivity to dirt & contamination like bugs and rain, and better high AOA operation. Trying to extract high lift coefficients in a low Re environment is hard to do: we run into boundary layer instability and laminar separation issues. With your wing, running at a Re of 6,000,000 it will help keep the dynamic nature of the flow more stable. Low Re's are in the under 500,000 range. Keep in mind that as you slow down, that reduces reynolds number, and there are plenty of airfoils that become hard to control at high angle of attack when running at lower speeds (like approach speed). That's one good reason never to yank on the "angle of attack lever" as I call it (the control stick) when the jet is slow. It simply cannot respond nicely when the boundary layer is so easily separated. At higher speed, you can get away with lots more. Wider chord wings are more tolerant of mis-handling by the pilot than narrow chord wings. Your wing is pretty wide @ 83 inches, which drives Re up and makes it naturally more forgiving in a high AOA situation. Out near the tip where chord lengths are shorter, the Re's are also reduced and so there's a tendency for tip sections to not hang in there so well as the wider chords mid-span. Its *one* of the factors that drive "tip stall", which we attempt to design around with geometric twist, stall strips, fences, slots, etc etc.

If that aero data plot you sent me is of YOUR airfoil, then yeah its a Riblett design. Harry certainly wasn't as sophisticated as his Big Industry or Government (NACA) counterparts, but he did really seem to have a good understanding and feel for the job. I actually had the pleasure of corresponding with him many years ago.

With that wing chord, you're in good shape. Reynolds number @5000 MSL, 240 mph (350 ft/sec) is 12.7 million. MUCH better than I thought. No issues should develop with laminar instability.

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#### Saville

##### Well-Known Member
Yes, the new prop hub and HD Gearbox added 4 inches to the nose. Requiring a new nosebowl and spinner design.

Did you make the new nosebowl? Or did Titan do that?

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#### TXFlyGuy

##### Well-Known Member
Did you make the new nosebowl? Or did Titan do that?
All fiberglass parts made by Titan. I did the prop, spinner, and nosebowl installation. Installing the propeller (90") is a pretty big deal, requiring two people.

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#### Yellowhammer

##### Well-Known Member
The T-51D is very close indeed. The minor cosmetic changes made to the aircraft over the last 8 years have really improved the appearance.

The spinner (correct 2 piece), nosebowl, and belly intake scoop have all been modified to look like the P-51. My plane has the correct scale wing at 28 feet span. This is a huge improvement over the clipped wing (24') version.

I am one of the few that have added inner gear doors. This makes the Mustang look much more authentic. But these add some weight, cost, and major complexity to the system.

The D model canopy is slightly larger than 3/4 scale. This was done to allow two adults to comfortably occupy the front and rear seat.

The T-51 landing gear has a slightly more narrow wheelbase than the P-51. I think this was a construction/build consideration, and a cost issue.
View attachment 98661
Absolutely stunning. Certain to turn heads. What kind of engine did you install?