Just a few shots of the latest project to come out of the Butcher Shop...or what stunt builders build when they  are not building stunt planes. The Shy Fox MkII is a MkI with a lower aspect wing. Both were designed by Dave Hull. It has not flown yet but will be soon. Power is an Enya 25 SS, ABC. For comparison I enclosed a shot of the MkI and Mk II side by side. Plans for the original MkI version can still be ordered from Model Aviation magazine.

Sorry, Super Slow Rat per NCLRA rules. 

I got a close up look at both when Pete came down for the Bob Palmer Stunt Contest. He's raced the Mk I with us before, but the Mk II is right off the assembly table and it looks really good. We had hoped to get some flights in after the stunt rounds were completed but didn't quite make it. Hope you get it in the air soon Pete and work out any bugs.

My own Mk II just had the outboard wing rebuilt after the overly aggressive pilot person put it into the pits at warp speed. Even when the pitman has soft hands, there is a limit to what the leading edge can take!

No plowing on either one of these, Motorman. They have plenty of span. I have flown “floppers” as a rent-a-pilot before and didn’t like them at all. The induced drag goes thru the roof at the top of the racing zone and they slow down. If you bring a pig to that party, your pilot needs to be a good whipper. The reason each of the proud owners touted for the super low A/R was the low form drag from the reduced frontal area and that they shake down impressively. Both those claims are nebulous. If you want to win, you have to be able to pass without slowing down, or you need “liberal” officiating and a strong pilot. And if the pig stalls on the first shake and does not reestablish flow and flying before it hits the ground (in other words, it is a flopper) you basically get close to the pit and crash there and hope it is in reach of the pitman and nothing important broke off. Liberal officiating helps here too. And if you have staked your design cred on such a design, you build it stronger and heavier each year to keep it from breaking during successive flops. So now it slows down even more at the top. True race plane de-evolution!

Ok. I’m not a fan of super low A/R racing planes. It does get the wing out of the way of the pitman which is the only redeeming value I have found. This was pointed out to me after too many beers at Muncie—by a pitman….

If it helps anyone, the wingspan on the Mk II is 34 inches. The area and thickness are unchanged. It also used the stock stabilizer size. The rest is unchanged. I prefer the Mk II because it is easier for the pitman and it flies just as good.

McSlow

PS—Tell us about your 24” slow rat, Motorman

I don't drink Beer

George,

The ShyFox plans are available from the AMA. You can go into the Members Only section and see them in the archives, including a very complete build article in the March 2010 magazine. The Mk II differs only in the wing planform. There are no released plans for the Mk II, just two sketches that I made and gave to a few guys that were interested. The root chord is 10-1/4" and the tip chord is 9-1/4". The wing LE is moved 1/2" forward in this version to maintain the  balance. Neither of my planes required nose/tail weight. I tend to use firm wood in the fuse and tail. Spar construction is the same, just a bit shorter. Just make up some root and tip templates per the sketch and stack-sand your rib set.

Again, in the interest of full disclosure, I didn't follow the plans when I built the Mk I stab and elevators. Kind of like Pete and his wingtips, the piece of wood I had was a bit bigger than the plans so I used it. The plans actually show both, so take your pick. The Mk II used the smaller stab. No difference in the way the two fly, really.

For anyone who has not tried the exact sewn hinges shown in the plans, you should. They are really bulletproof when combined with the spruce spars. They work equally well on basswood surfaces that I use for Goodyear, Mouse, Rat, and Quickie Rat tails. The problem I have when I tell people about sewn hinges is that they remember carpet thread and a million stitches along the length of the surfaces. (Like Frankenstein's sutures.) This is unnecessary with modern materials, draggy, takes more time to do, and is butt-ugly. The second issue is that guys all fondly remember the "best" material to use. I try not to get involved in these conversations any more. People do what they know--even if it has long since been improved. When a guy tells me how great 1/2A Dacron flying lines work but won't try Spectra, the receive channel just isn't turned on. Or dental floss. Or carpet thread. Or, the super techie dude,  who has got to use Kevlar thread. Sure Kevlar is strong, but for a sewn hinge, it is harder to work with and you need some pretty small stuff. If you have a 100 year supply of Soviet Kevlar that you need to use up, go for it!

Well, I guess if Rad doesn't do beer, he must not have been the pitman in question. Or else I drank too many and can't tell the story right! Bob did a great job pitting the heat races at the Nats that year. Most races are won in the pits, so try not to hand a rent-a-pitman a plane with some unusual trick setup. If the teams have to split up for the final, that pitman may only get 5 minutes to figure out your setup. Less if he has to go fill up the refueling bottle. Most pitmen are very familiar with the setup shown in the ShyFox plans. This plane has probably been pitted by all of them!

McSlow

So true about pitmen.  When Melvin and I were flying together  in the Shoestring event I would tell to set the prop to his satisfaction when he pitted my plane.  Other than mouse it was only event I would fly because of rules at the time.   Guess I will have to pull out plans of the Sly Fox.