Stilleto 502 Tribute

[Pat Johnston]

Terry Mitchell of Oregon sparked a thought about making Les McDonald's Stiletto into one of the "502" series planes.  It only took a few hours to setup both the IC and Electric versions in ACAD.  This size plane makes a terrific flyer while being a little smaller and easier to fly and transport.  Give the PDF files a look over and see what it looks like.  I am contemplating doing a Bob Baron Avante next as a great tribute plane to a real legacy.
Pat Johnston
Idaho Skunk Works

[Dan McEntee]

    Was it you Pat, that did the plans for the "Little Legends" 1/2A Series? They all used the same wing basically, just different tips and maybe flap outlines? I think it was the Stiletto, Genesis, and I forget the other three? Why not just go for the whole enchilada and recreate those in this size?? The Avante is a good addition also.
  Type at you later,
  Dan McEntee

[Brent Williams]

Very cool, Pat!

[Pat Johnston]

Dan,
Not me on the 1/2A little legends.  Thanks for the compliments.
Pat

[Steve Helmick]

Patrick, what size is that OS FP shown on the first plan...the .25, .35 or .40? I looked and looked, but didn't see anything about that. The 11" prop seems like a lot for a .25.  Steve

[Paul Walker]

Looks good Pat.

My one comment is that I don't remember the Stiletto having such a tall vertical tail. 

[Dave Hull]

Stiletto 35

[Pat Johnston]

Paul, those plans posted look very familiar and are likely the ones I referenced to draw the original Stiletto plans from. Would you believe this was the second plane I drew on ACAD in about 1992 (for Tom Dixon)? The first plane was the Flight Streek. This is as close to ground zero it gets for my starting drawing planes. Woo! 30 years!
Steve, I am pretty sure that the engine shown is a FP35/40. My flying buddy, Scott Danner, puts the FP35 on his 502 series planes. They work out very well. As for a FP25 swinging a 11” prop, that might be more than most people would think reasonable, but I used a 11-4 BY&O that was very well cleaned up on my Nobler, and Brett once commented that it was “noticeably overpowered”. I think Dave Gardner even played with 11” props on his 25’s. It can be done, but not for the faint of heart.
Pat Johnston
Idaho Skunk Works

[Dan McEntee]

Stiletto 35

  True or false??  Thinking back, I heard or read some where that the wing in this version was more or less a SIG Chipmunk wing? I'm sur Les may have covered that in that multi part Stunt News article several years ago, but just can't get into all that reading right now. I have this kit and some other versions of the plan, I think.
  Type at you later,
  Dan McEntee

[Dave Hull]

Dan,

Of Chipmunks and Stilettos….

SIG CL-3 Van Loo Chipmunk:  wingspan 54”  (box reference)
SIG CL-19 Stott Chipmunk:  wingspan 53.5”, area 570 in2
Stiletto “35” McDonald (Mathis kit reference): wingspan 54”  (Was apparently published in June 1974 M.A.N.)
Stilleto [sic] 502 Johnston: wingspan 53.25”

I don’t have a CL-3 plan handy to compare to the Stiletto 35, so I can’t really say how close the two are. They do both appear to have swept main spars… and similar planking?

I assume others would know more....

[Dan McEntee]

Dan,

Of Chipmunks and Stilettos….

SIG CL-3 Van Loo Chipmunk:  wingspan 54”  (box reference)
SIG CL-19 Stott Chipmunk:  wingspan 53.5”, area 570 in2
Stiletto “35” McDonald (Mathis kit reference): wingspan 54”  (Was apparently published in June 1974 M.A.N.)
Stilleto [sic] 502 Johnston: wingspan 53.25”

I don’t have a CL-3 plan handy to compare to the Stiletto 35, so I can’t really say how close the two are. They do both appear to have swept main spars… and similar planking?

I assume others would know more....

   I have all those plans and kits, and the related wingspans include the respective tip shapes also. I think I may have done an overlay of them to compare them tip rib to tip rib and that is maybe what makes that stick in my mind. Planking and overall construction is very similar except for how the Stiletto landing gear mounts. We have some crappy weather days coming up and maybe I can revisit that. I also have a Walter Umland kit of the .35 model, but I don't think I ever really looked at that one to see what it looks like or if he has any other references on the plans.

  Type at you later,
   Dan McEntee

[Brett Buck]

As for a FP25 swinging a 11” prop, that might be more than most people would think reasonable, but I used a 11-4 BY&O that was very well cleaned up on my Nobler, and Brett once commented that it was “noticeably overpowered”.

   I think the fact that it was running under 4.5 seconds/lap was a good tip-off - with, as I recall, a tiny venturi (.220-.225, maybe?)!

    This illustrates both that these engines are vastly more powerful than ancient 35s, and also, that trying to run the largest prop it will turn is a big mistake. I have seen people run stock-off-the-pegboard Tornado 10-4 3-blades on a box-stock 20FP, that is more load than a cleaned up 11-4 2-blade. It obviously is far from optimum, but you aren't going to hurt the engine doing it, this is not a McCoy 35.

     It will happily turn a 11" prop, but, that is *vastly too efficient* and transferring all that power to the airplane just makes it go like a bat out of hell. So, what you need to slow it down is less efficiency, since it is already at the bottom of the pitch range you can get, that means less diameter. This also frees up the engine so it responds rather than run flat all the time.

    People wildly underestimate what these engines can do. And not just FPs - I flew full stunt patterns with an ST46 using as little as a 9-4, and as much as a 14-6, straight out of the box with no changes. I follow Al Rabe's recommendation to some extent - don't worry about the engine, if the prop is wrong, the airplane will tell you. Note that at the time, using more diameter was the only degree of freedom you could reasonably explore, and you judged the power of engines by how much diameter they would turn, and that was how you got performance. This is *long gone* with modern engines, you have so much power you can afford to/have to figure out a way to waste it in the most effective way possibl

   I suggest smaller props not because the 'engine won't turn' bigger props - it will - but because it allows you to get reasonable speed and reasonable response at the same time.

     Brett

[Pat Johnston]

To further explain the Stiletto 502. The wing is the same as the rest of the “502” series planes with the tips to approximate the shape of the Stiletto tips. The fuselage is scaled down to fit the 502 format for wing to tail proportions. The overall design is to provide a look which the viewer believes is a scaled down Stiletto. I highly suspect that the leading edge taper, aspect ratio, flap configuration etc. are not the same. Since the wing was from the 502 series, it conforms to good overall stunt proportions. It is kind of the way my Mustang 626 gave the scale people satisfaction and the stunt people the same.
Back to the Nobler with the FP25. The setup was from Leonard Neumann which had a plugged boost port, a relatively stock venturi (.257”) and a ST NVA (4 mm). The lap times were between 4.8 to 4.9 seconds on 58’ lines (E/E). I don’t remember the RPM, but I think it was in the 9500 to 10,000 range. Another factor was the plane started out at 36 ounces and gained an ounce with lead in the tail. Needless to say, a 37 ounce Nobler has nice flying qualities. It was a lot of fun.
Pat Johnston
Idaho Skunk Works

[Curare]

Pat, is there any reason you've chosen to use the icecream cone airfoil on these?

[Pat Johnston]

I find the ice cream cone airfoil to be very effective and lends itself to some interesting developments with ACAD as the drawing platform.  For example, it is easy to change the high point say from 22% at the root to 18% at the tip. Or, on my Bearcat 617 the high point is 20% back along the whole wing, but the root is 18% thick and the tip is 16% thick. The result is a relatively high lift wing with reasonably low drag tips. Bob Hunt subscribes to lower drag tips for a possible turbulence reduction. The ultimate configuration is evident in my “Epiphany” series of designs which have a pure elliptical wing planform. Think British Spitfire. The tips are very low drag. We’ve seen success in the Epiphany series from the 202” version all the way to the big 710” version. See Crist Rigotti’s build thread on this forum. He started with ribs from the 617” version. Crist builds a beautiful plane.
Pat Johnston
Idaho Skunk Works

[Les McDonald]

Dan,
Not me on the 1/2A little legends.  Thanks for the compliments.
Pat

Steve Buso did the plans for the "Little Legends".

[Les McDonald]

Dan,

Of Chipmunks and Stilettos….

SIG CL-3 Van Loo Chipmunk:  wingspan 54”  (box reference)
SIG CL-19 Stott Chipmunk:  wingspan 53.5”, area 570 in2
Stiletto “35” McDonald (Mathis kit reference): wingspan 54”  (Was apparently published in June 1974 M.A.N.)
Stilleto [sic] 502 Johnston: wingspan 53.25”

I don’t have a CL-3 plan handy to compare to the Stiletto 35, so I can’t really say how close the two are. They do both appear to have swept main spars… and similar planking?

I assume others would know more....

Richard Mathis did two different Stiletto .35 kits. The first were directly off the MAN plans and the second version used ribs from the SIG Chipmunk, purchased from SIG. These were two entirely different airframes.

[Dan McEntee]

Richard Mathis did two different Stiletto .35 kits. The first were directly off the MAN plans and the second version used ribs from the SIG Chipmunk, purchased from SIG. These were two entirely different airframes.

     Ah, this is where I think I had the idea in my head about this. I think the first plans I acquired and began reading about it was back in the late 1980's or early 90's.. I have several different plans for the .35 Stiletto, plus a Mathis kit, and I think I have a Walter Umland kit of it also. I don't think I have ever check out those plans to see what he based his kit off of. Out of all of that I think I should be able to build one!!
     And I think it was Walter that revived the Little Legends, proposing to put out a kit with accompanying plans that would let you build any one you wanted since the wing was the same, all you had to do was decide on which outline you wanted. There was interest, and I think I got plans from him for those, but the kit didn't happen due to a health issue at that time.  Thanks for the clarification Les !
   Type at you later,
   Dan McEntee

[Dave Hull]

Hmmm. Interesting about the two "entirely different" kits for the Stiletto 35. I'm guessing that the kit shown in post #6 is the earlier MAN non-SIG-rib kit. If I recall correctly, these ribs looked like they were sawed and sanded, not die-cut as I imagine the Chipmunk ribs would have been?

Is there a summary of the differences between the two designs?

Dave

[Paul Walker]

When I hear Stiletto, this is what I see.