FTFF 2017 International Air races: Design-Off

[FAI-F1D]

I'm in either a Pearson Williams 0W-1 or a Chambermaid. I'm not liking going up to 48" span for the Smoothie, and I'm not liking the idea of taking a 25" Chambermaid to speeds my similarly sized rockets only maintain for 3 seconds.

I'll do one of those, but the mention of requiring a 7' span on. A Lockheed defeats the whole purpose of this event. It also discourages building certain platforms since they are then uncompetitive in the race in addition to being cumbersome. Not a good idea at all.

 

[localfiend]

I'm in either a Pearson Williams 0W-1 or a Chambermaid. I'm not liking going up to 48" span for the Smoothie, and I'm not liking the idea of taking a 25" Chambermaid to speeds my similarly sized rockets only maintain for 3 seconds.

I'll do one of those, but the mention of requiring a 7' span on. A Lockheed defeats the whole purpose of this event. It also discourages building certain platforms since they are then uncompetitive in the race in addition to being cumbersome. Not a good idea at all.

It doesn't look like you lose that many points for not being exactly 1/6 scale.

Are you looking at planes that aren't race planes? What lockheed race plane would have 1/6 scale size of 7'. If you guys are talking about building airliners or something, it would make sense that they wouldn't be competitive.

 

[Michael9865]

Entry
Michael763
Miles M-5 Sparrowhawk G-ADWW
http://forum.flitetest.com/showthread.php?29391-Flite-Fest-2017-Miles-M-5-Sparrowhawk

This will be fun. I hope its 56" wing will fit in my car. LOL

Thank you for taking the time to organize this. I agree that this encourages us to advance our knowledge and our hobby. Not to mention the fun factor and community already looking forward to FF 2017 already.

 

[FAI-F1D]

Ok, I've made a decision... Smoothie simply will not work at this scale..at 1/6 scale, the fuselage cross section will cause me to have to special order a prop from Germany to get the performance want.

Enough of my whining! I'm in with a Folkerts Sk-4. This is a seldom seen build...the Sk-3 is much more popular for reasons I don't understand, but I'm looking forward to having a bright red 33" pylon racer!

 

[Mid7night]

Ok, I've made a decision... Smoothie simply will not work at this scale..at 1/6 scale, the fuselage cross section will cause me to have to special order a prop from Germany to get the performance want.

Enough of my whining! I'm in with a Folkerts Sk-4. This is a seldom seen build...the Sk-3 is much more popular for reasons I don't understand, but I'm looking forward to having a bright red 33" pylon racer! View attachment 74105

I don't know if it matters, but I've already entered with the SK3, and by all accounts I can find they are visually identical. The real things had different powerplants, but otherwise the SK4 was basically a copy of the SK3. If you have data to the contrary, I don't mind the competition, but I think it would be better if we didn't have such similar designs.

Sources:
Wikipedia
Popular Mechanics

 

[TEAJR66]

I don't know if it matters, but I've already entered with the SK3, and by all accounts I can find they are visually identical. The real things had different powerplants, but otherwise the SK4 was basically a copy of the SK3. If you have data to the contrary, I don't mind the competition, but I think it would be better if we didn't have such similar designs.

Sources:
Wikipedia
Popular Mechanics

Revel in the competition. I claimed the Firecracker in the original thread and I hope several others find their way to this design. Someone else claimed it here also. Might could lead to some collaboration.

The more great minds that tackle these designs, the better the final product.

 

[RCBuildIdeas]

RCBuildIdeas
Percival Mew Gull
I'll add a build link when I have a first draft of plans.

Here's a link to my build thread:

http://forum.flitetest.com/showthread.php?29646-FF2017-Int-Racers-Percival-Mew-Gull

 

[Mid7night]

Revel in the competition. I claimed the Firecracker in the original thread and I hope several others find their way to this design. Someone else claimed it here also. Might could lead to some collaboration.

The more great minds that tackle these designs, the better the final product.

Oh, absolutely! And I hope FAI-F1D didn't take what I said the wrong way - I have no right to 'tell' him what to build, and that was not my intention in the slightest.

One of the stated goals of this competition is "Friendly Forum Banter", so in the spirit of that... SK3 vs. SK4?!? BRING IT!

 

[FAI-F1D]

Mid7night, I had a competitor back in the day who insisted that the Sk.4 was a completely different airplane. I need to drag out a 3 view that I have archived and try to get a definitive answer. What I can assure you, having looked at your build thread, is that our builds will be vastly different. Yours is a traditional, beginner friendly build. Mine will not be. I have a thirst for speed, and that's going to require some creative tricks to keep the firewall attached to the front of the airplane.

It should be a fun comparison, and yours looks already like it should fly well. You ever flown a 100 mph airplane? I think yours is capable of it!

[Smack]
My sk4 is going to show yours how to fly.
[\smack]

 

[TEAJR66]

I have a thirst for speed, and that's going to require some creative tricks to keep the firewall attached to the front of the airplane.

More Tape!!!

 

[FAI-F1D]

More Tape!!!

Kevlar tape?

 

[HilldaFlyer]

No, no, no

Let's try some fiberglass tape ->

 

[Mid7night]

Mid7night, I had a competitor back in the day who insisted that the Sk.4 was a completely different airplane. I need to drag out a 3 view that I have archived and try to get a definitive answer. What I can assure you, having looked at your build thread, is that our builds will be vastly different. Yours is a traditional, beginner friendly build. Mine will not be. I have a thirst for speed, and that's going to require some creative tricks to keep the firewall attached to the front of the airplane.

It should be a fun comparison, and yours looks already like it should fly well. You ever flown a 100 mph airplane? I think yours is capable of it!

[Smack]
My sk4 is going to show yours how to fly.
[\smack]

Regarding the 100mph question...this may sound weird... I've never flown a powered plane that fast, but I have flown slope gliders over 100. 112mph is my fastest recorded, but I just maidened a new one I suspect went faster.

As to the similarities; the PopMech source makes mention of a few design tweaks, but largely the modifications were a better (metal) prop and more powerful engine. I don't dispute there weren't differences, but if your scaling-math arrived you at a 33" wingspan too, then we'll have a most interesting and entertaining race on our hands.

I look forward to spying, I mean watching your build log to see your take on this plane.

 

[Michael9865]

No, no, no
Let's try some fiberglass tape

May need to order some water-proof Foamboard to go with this tape to make one very strong wing.

 

[RCBuildIdeas]

The link to my build thread isn't working on post #2 of this thread.
I'll try again, here's a new link:
http://forum.flitetest.com/showthread.php?29646-FF2017-Int-Racers-Percival-Mew-Gull

 

[willsonman]

Gotcha covered

 

[FAI-F1D]

Regarding the 100mph question...this may sound weird... I've never flown a powered plane that fast, but I have flown slope gliders over 100. 112mph is my fastest recorded, but I just maidened a new one I suspect went faster.

Not really that surprising. Sloping definitely lets you get some serious speed. But you must tell what this new critter is!

As to the similarities; the PopMech source makes mention of a few design tweaks, but largely the modifications were a better (metal) prop and more powerful engine. I don't dispute there weren't differences, but if your scaling-math arrived you at a 33" wingspan too, then we'll have a most interesting and entertaining race on our hands.

Yeah, gotta go digging. I've got that silly 3-view somewhere. It seems to be quite nicely buried.

 

[Mid7night]

Not really that surprising. Sloping definitely lets you get some serious speed. But you must tell what this new critter is!

The 112mph plane was a PSS Ki-84, and it weighed about 65oz to 70oz. My newest one is a PSS FW-190, weighing 75oz. The Focke Wulf also has a slimmer nose/fuse profile, that's why I think it has better speed potential.


Not sure if there were any +100mph passes on this flight, but there were a few good zingers:

 

[HilldaFlyer]

The 112mph plane was a PSS Ki-84, and it weighed about 65oz to 70oz. My newest one is a PSS FW-190, weighing 75oz. The Focke Wulf also has a slimmer nose/fuse profile, that's why I think it has better speed potential.

Can you explain how the wind pattern in the above video propels the plane? I understand the phenomena of dynamic soaring, a plane crosses boundary layers of slower to faster moving air. What I can't see in the video is the pattern of the plane with respect to the boundary layer. Looks like the wind is right at your face. Thanks

 

[Mid7night]

Can you explain how the wind pattern in the above video propels the plane? I understand the phenomena of dynamic soaring, a plane crosses boundary layers of slower to faster moving air. What I can't see in the video is the pattern of the plane with respect to the boundary layer. Looks like the wind is right at your face. Thanks

The wind direction is straight at us, but locally it is also rushing up the cliff face so there is a band of rising air providing compression lift near the ridge. The compression-lift band is mostly what sustains the flight - you can see seagulls and other soaring birds do this all the time. Nominally, the flight pattern is a wide "U" shape. It doesn't make use of boundary layers like backside DS'ing does; instead the left and right extremes are called "pumps", where you pull up and out slightly into the wind, trading airspeed for altitude and gaining some energy from the wind as you pull, then stall-turn at the top to fall back down trading altitude back for airspeed.

When and where you pump up partially determines how much energy you add to your momentum from the oncoming wind, because there are always local irregularities in the cliff/slope face that will naturally concentrate updrafts. How efficiently you fly through "the slot" (the bottom of the U) determines how much energy you retain into the next pump. If you gain more on the pumps than you use through the slot, you build speed (and fun).