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*Official* Foam Board Top Speed Challenge

#1
Hi guys, I’ve noticed some people recently like @IdoAllMyOwnStunts doing insane top speed runs with foam board, and apparently the current top speed is 175mph, I would like to compile everything known about top speed runs and log the record. Might even try my own hand at it too 🤔 Lets work out the rules down below!
 
#2
First thoughts are, what is legal for building materials? Of course carbon spars will be necessary but we need to ask ourselves
•Is composite sheeting legal?
•Can we use balsa/basswood/other wood for control surfaces, reinforcement, etc
•What electronics are legal, while it would be extremely fun, is a $300-$400 inrunner setup worth being legal?
 

Mid7night

Jetman
Mentor
#4
Ben Harbor AKA @Mid7night did a speed challenge a while ago. He has some videos on his channel with his entry. https://www.youtube.com/channel/UCBaHOwWwjPtH46uFnwKST5Q


Cheers!
LitterBug
It was VERY "unofficial" to be sure, and I had some issues with my GPS speed readings. I think my highest reliable speed was 154mph. But don't forget about Joshua Finn @FAI-F1D! I think he holds the record between us two - I can't say for sure, but I think it was 175mph.

FWIW: We stuck to "mostly foamboard" for our challenge. We allowed carbon fiber tubes/rods for spars, and Finn used thin plywood on one of his wing-saddle attachments which we also thought was fine. I also used paint stir sticks on my belly as skids, and in a few places to reinforce a nose-repair.

But the flying surfaces, control surfaces, all the main construction was foamboard, hot glue and tape. We didn't get into sheeting or glassing at all, and in my opinion that would kinda defeat the purpose of a "foamboard speed plane". Once you sheet or glass, the foamboard is no longer the structural element, it's a substrate - which is exactly the proper way to use foam under glass - but then you no longer have a "foamboard plane", you have a "foam core glassed plane".
 
#5
It was VERY "unofficial" to be sure, and I had some issues with my GPS speed readings. I think my highest reliable speed was 154mph. But don't forget about Joshua Finn @FAI-F1D! I think he holds the record between us two - I can't say for sure, but I think it was 175mph.

FWIW: We stuck to "mostly foamboard" for our challenge. We allowed carbon fiber tubes/rods for spars, and Finn used thin plywood on one of his wing-saddle attachments which we also thought was fine. I also used paint stir sticks on my belly as skids, and in a few places to reinforce a nose-repair.

But the flying surfaces, control surfaces, all the main construction was foamboard, hot glue and tape. We didn't get into sheeting or glassing at all, and in my opinion that would kinda defeat the purpose of a "foamboard speed plane". Once you sheet or glass, the foamboard is no longer the structural element, it's a substrate - which is exactly the proper way to use foam under glass - but then you no longer have a "foamboard plane", you have a "foam core glassed plane".
Ok so maybe we do a class setup with an unlimited class with composites like fiberglass and one with an actual foam board finish because it appears the foam board started getting pushed past its elastic limit at 175 mph. I dont think fiberglass is in too bad of heart though because its fairly cheap and in the spirit of DIY
 

PsyBorg

Wake up! Time to fly!
#6
Be interesting to see how this pans out with the changes in laws. I would be very leery posting videos of things going over 100 mph with the gubments checking on you tubes for people posting without part 107 + doing questionable things now.

I wont be posting any more flights until clarification whether the F.A.A is gonna witch hunt people flying anything under that very questionable wording about videos and the furtherance of a business. There is no black or white whether your video with a sub 250 aircraft is still furthering a business because it is posted on you tube who has now decided they can add ads into any or all video's whether the content provider is monetized or even wants them or not.
 
#7
Be interesting to see how this pans out with the changes in laws. I would be very leery posting videos of things going over 100 mph with the gubments checking on you tubes for people posting without part 107 + doing questionable things now.

I wont be posting any more flights until clarification whether the F.A.A is gonna witch hunt people flying anything under that very questionable wording about videos and the furtherance of a business. There is no black or white whether your video with a sub 250 aircraft is still furthering a business because it is posted on you tube who has now decided they can add ads into any or all video's whether the content provider is monetized or even wants them or not.
If the content creator is not receiving income it it therefore not a commercial flight for CERTAIN, nonetheless a video of someone flying an rc plane is not really that big of a deal for the FAA. I doubt the witch hunt will happen the way you mention, however I think laws will be more strict. Maybe we all just have to go to “mexico”
 
#8
Just my 2¢ but I think we should make an unlimited category that as long as there is foam board holding the shape of the airframe being the core it will be legal and perhaps a true “structural foamboard” class that composite skins are illegal but carbon spars, wood reinforcements, and such are legal. Covering of the wing must be a non structural material such as tape, covering film, etc
 

The Hangar

Fly harder!
Mentor
#9
Just my 2¢ but I think we should make an unlimited category that as long as there is foam board holding the shape of the airframe being the core it will be legal and perhaps a true “structural foamboard” class that composite skins are illegal but carbon spars, wood reinforcements, and such are legal. Covering of the wing must be a non structural material such as tape, covering film, etc
To me it should be all foamboard except for the spar and plastic hinges for the control surfaces. Sure, fiberglassing is cool but it kinda defeats the purpose of making foamboard hit 200mph...
 
#10
To me it should be all foamboard except for the spar and plastic hinges for the control surfaces. Sure, fiberglassing is cool but it kinda defeats the purpose of making foamboard hit 200mph...
I definitely think Kevlar hinges are the way to go here period. To me its more of a safety thing than a speed increase. If you’re losing control surfaces at 200 mph to beat the record its really not cool. Someone will eventually get hurt if thats an issue. I have an idea for that though.
 

LitterBug

Troll Spammer
#12
Paranoia from the FAA putting overreaching restrictions on the hobby (aka 100mph speed limits) is part of it. The othe is it takes a really large amount of wide open space to fly these speeds.
 

L Edge

Elite member
#13
Here are planes that are doing 200mph (300ft/sec) and you want foam to handle it? No way. How about 50 g's in the corner. At the end of the season, your plane(s) are retired due to high loads and vibrations. I had one fold up in a tight turn. We used 60/65% nitro and turned a prop at 21,600 in order to get the 180/200 speed. Think of the watts that you would need to duplicate that.


Looking from the pilot's viewpoint, very few could can handle these speeds and in the hand's of a wrong pilot, it's a death weapon. In fact, a pilot has to be verified before flying a jet/pylon racer at a AMA club field.
 
#14
Here are planes that are doing 200mph (300ft/sec) and you want foam to handle it? No way. How about 50 g's in the corner. At the end of the season, your plane(s) are retired due to high loads and vibrations. I had one fold up in a tight turn. We used 60/65% nitro and turned a prop at 21,600 in order to get the 180/200 speed. Think of the watts that you would need to duplicate that.


Looking from the pilot's viewpoint, very few could can handle these speeds and in the hand's of a wrong pilot, it's a death weapon. In fact, a pilot has to be verified before flying a jet/pylon racer at a AMA club field.
Yeah, well we didn’t ask really for your opinion on safety mate but a 5000w setup on 6s will push 300mph out of a composite bird and will likely push a dtfb bird to around 200.
 

FoamyDM

Building Fool-Flying Noob
#15
When I build my U-2 out of Foam Board.... I want her to kick on "afterburners" and get a major case of the Zoomies. and 150mph+ seems fast enough. To me the best experience will be through LR FPV. as you run out of field and orientation quick at 300ft/sec even on 40 ac. farm.

My Vote - Mostly Foam - no Glassing. other materials as a minor component to improve durability.
 
#16
When I build my U-2 out of Foam Board.... I want her to kick on "afterburners" and get a major case of the Zoomies. and 150mph+ seems fast enough. To me the best experience will be through LR FPV. as you run out of field and orientation quick at 300ft/sec even on 40 ac. farm.

My Vote - Mostly Foam - no Glassing. other materials as a minor component to improve durability.
No one new is really going to contribute to this challenge because of the FAA it seems. Oh well. Good luck pushing 150+ with less than a 12s setup lol. Cant wait to see what it does!
 

quorneng

Master member
#17
Speed costs money.
I my opinion the winner will be the person who can afford to (or wants to) spend the money unless the rules are very prescriptive on the 'what and how' you can use.
 
#18
No one new is really going to contribute to this challenge because of the FAA it seems. Oh well. Good luck pushing 150+ with less than a 12s setup lol. Cant wait to see what it does!
I really wouldn't think the FAA will be camped out near any potential flying sites (in the entire US) with a radar gun. Silly thought, right?

It may have been mentioned here already but how would someone compete without access to a radar gun? Just asking. Seems like a prerequisite.
 

Piotrsko

Master member
#19
How many of you people actually have gone over a hundred clocked? Not to even mention going 100+. Then there's the issue of keeping it at that speed, a place big enough to not pull the wings off doing a turn, structural integrity......... had aileron flutter somewhere north of 100 in a dive, and by the time the sound registered as WTF?, the plane exploded and was raining very small parts. The biggest piece was the battery pack but it no longer had a wire/connector.
 

FoamyDM

Building Fool-Flying Noob
#20
I really wouldn't think the FAA will be camped out near any potential flying sites (in the entire US) with a radar gun. Silly thought, right?

It may have been mentioned here already but how would someone compete without access to a radar gun? Just asking. Seems like a prerequisite.
GPS? A Sound Speed App? I admit to not knowing the limitations of them so they may not track those speeds. Yes posting vid of a plane traveling definitively more the 100+mph seems to be a violation according the Current FAA 14 CFR Part 107 rules. (see section highlighted in black)
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In a interest of being good Stewarts of the hobby, many will not be on board.
Forces from Air speed are (0.00256)(V^2) Velocity V is in mph.
60 mph = 9 psf, 100mph = 25.6, 150 mph = 57.9 psf, 200 mph = 102 psf

3x speed = 6x forces on the plane. (let alone turning g-force loads)
an exciting challenge.