• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Foamboard Ultimate Speed Challenge

FAI-F1D

Free Flight Indoorist
#1
Jared Hughes on the Flite Test Fans facebook page raised the suggestion that we have a contest of sorts to see just how fast a legitimate foamboard airplane can go. He mentioned setting up a thread here, but doesn't look like he's gotten around to it, and I've got a set of preliminary rules to toss into the game.

a2646291-12-13.jpg

Please understand before I get started, that this is not intended to be the official start of a forum contest, nor is it intended to compete with Joshua Orchard's scale air race for FF 2017. That said, I would very much like to see this held as an unofficial event at FF 2017.

I'm proposing that we race our models on our own time at our own fields and make speed runs recorded using a smartphone Doppler analyzer app. There are several available fairly cheaply in the Google play store. We need to all agree to use the same app. Also, it is very important that we eliminate the contribution of wind to the event, so the rules should include something like two runs in each direction, with the results averaged. The entries should be videoed of course.

Now, let's talk rules. This needs to be kept reasonable while allowing for as much performance as practical. As such, let's try this as a proposed set of design rules:

1. Completed model designs must be published. Make it possible for others to use your design
2. Keep it in the spirit of Flite Test--use actual foam board--no fiberglass or other skins, including tape. Actual, regular foamboard. It's perfectly reasonable to allow removal of the paper, as that's not a structural advantage, but it does eliminate humidity issues and allows further streamlining.
3. Tape reinforcing should only be allowed on firewall attachments, wing leading edges, and control surface hinges. Skinning wings in tape is not in keeping with foamboard construction
4. No carbon except for a single carbon wing spar--this allows for safe wing construction on closed courses without making these into disguised composite builds
5. Firewalls from any material desired, but no molded front ends.
6. Paper anywhere you like it.
7. No use of epoxy anywhere, or sealants intended to stiffen paper coverings.
8. Keep it reasonable: maximum battery should be a 3s 2200 or less. I don't believe we need a C rating restriction. If you're needing 70C batteries, you probably designed your propusion system wrong.
9. No folding propellers. This is not to restrict glide performance, but rather to eliminate expensive hotliner propellers.
10. Let's restrict cost further by putting a $50 cap on motors. This cost should be the retail cost of the motor with shipping ignored. No lowballing through clearance sales or swap meet trickery.
11. No cost restrictions on ESC's, servos, or receivers. High end electronics will not provide enough advantage to impact the outcome. If you want to use MKS servos, it's your wallet, not mine.
12. You can use other people's designs, provided they are credited and you clearly document any changes. The goal is speed. Get it any way you can within the design restrictions.

Also, the current speed record foamie at 139 mph:
a1630571-108-PC250018.jpg
 

nerdnic

nerdnic.com
Mentor
#2
I think this is a great idea! My thoughts are that if we are doing an ultimate speed challenge then there should be no limit on cells. If anything do an overall speed winner, and then maybe a winner per cell class. I think the goal should be how fast can a dtf plane go, not how fast can you go on 3s/4 etc.

You mention that tape is not allowed, what's the thought behind this? Adding a layer of tape over your foam is common and makes it more slippery. Without this option you're left with paint which adds more weight.
 
#3
Oh boy, crazy nic here already is pushing beyond 120, dont give him ideas :)
Well, rule 12 syas that I can get speed any way I can. Rocket engines? I love rocket engines.
 

FAI-F1D

Free Flight Indoorist
#4
I think this is a great idea! My thoughts are that if we are doing an ultimate speed challenge then there should be no limit on cells. If anything do an overall speed winner, and then maybe a winner per cell class. I think the goal should be how fast can a dtf plane go, not how fast can you go on 3s/4 etc.
Well, that's one take on it. There are some seriously fast racers out there flying 3s setups. I ran some numbers that indicated that 200 should be possible on 3s. At that point it becomes a question of whether foamboard will even let you go that fast.

4s could of course be easily justified, and I'm open to that. Anything more and I'm concerned that we're going towards a horsepower race that could get downright dangerous. Thoughts from the community?

You mention that tape is not allowed, what's the thought behind this? Adding a layer of tape over your foam is common and makes it more slippery. Without this option you're left with paint which adds more weight.
You hit exactly on the thought behind it. This is a foamboard challenge. The more reinforcements and refinements you allow on it, the less it is a foamboard contest and the more it drifts down the slippery slope of an unlimited, no holds barred speed contest. Banning all non-foamboard streamlining technologies is a convenient way of closing that door.

Oh boy, crazy nic here already is pushing beyond 120, dont give him ideas :)
Well, rule 12 syas that I can get speed any way I can. Rocket engines? I love rocket engines.
I'm thinking we should stay away from that, but if someone does come up with a foamboard rocket plane, we can let the community decide what to do. It would be seriously cool to get one going that actually accomplishes the design goal. Peter's Javelin FPV rig is the only really successful one I know of. He destroyed a huge number of prototypes getting there unfortunately.

All that said, I think that if rockets enter the picture, they need to be in their own class. We probably can't get an accurate Doppler measurement on them anyway.
 

Nerobro

A Severe Lack of Sense
#5
If the challenge is foamboard, why are we making the powerplant a factor? (I'm asking because i'm.. more than interested in this..) Is this a "skill in powerplant design" or a "skill in aircraft design"?

I'd propose a reasonable (common/cheap) motor and battery combination. Say, a 2204 motor, and 2200 battery. Then people can go wild making the slickest, lightest, lowest drag airframes they can come up with.

The carbon spar, should be specified. (I don't like the carbon spar, period... but that's for another time.)

Now, while we're allowed to remove layers of paper, can I ADD layers of paper?
 

FAI-F1D

Free Flight Indoorist
#6
If the challenge is foamboard, why are we making the powerplant a factor? (I'm asking because i'm.. more than interested in this..) Is this a "skill in powerplant design" or a "skill in aircraft design"?
The original goal was to see how fast a foamboard airplane can go, so I guess the answer to your question is somewhere between "both" and "neither". Maximum speed demands flying skill, trimming skill, building skill, a good design, and a good power system. Since we're specifying that participants must state what their power system is and we're capping the cost of the motor, it shouldn't put anyone at a disadvantage. Everyone has access to ecalc if they're willing to pay the $5/year subscription, so they can take other people's power systems and experiment with them.

The carbon spar, should be specified. (I don't like the carbon spar, period... but that's for another time.)
It's for those of us in wet climates, and it's a fudge factor for those with shaky thumbs so they don't fold their wings at high speed. ;)

Now, while we're allowed to remove layers of paper, can I ADD layers of paper?
Hmmm...can others weigh in on this one? I hadn't expected that question. :confused:
 

Nerobro

A Severe Lack of Sense
#7
The original goal was to see how fast a foamboard airplane can go, so I guess the answer to your question is somewhere between "both" and "neither".
Sorry, I lost the plot there. :) "how fast can foamboard go" Got it.


It's for those of us in wet climates, and it's a fudge factor for those with shaky thumbs so they don't fold their wings at high speed. ;)
Smaller wings and shorter wingspans goes a long way in that regard... Now if I can...

Hmmm...can others weigh in on this one? I hadn't expected that question. :confused:
If I can weigh in on my own question, I can see it two ways. Once you start doubling, tripling, otherwise thickening the skins on DTFB, and perhaps building fillets with paper, you end up building a cardboard/fiberboard plane. That's my excuse for "no".

It's cheap, it's do-able for anyone who can build a DTFB plane... It could get you strength that might even exceed carbon rod (which is a very specialist material..) So it's not a limiting factor. Anyone with a few books, some elmers white glue, and notebook paper could replicate what i'm thinking.

Are we going to be limited on adhesives? :)

I need to go buy some foamboard...
 

earthsciteach

Moderator
Moderator
#8
This is exciting! I won't be participating, but I will be sitting back munching on the popcorn. This is really going to push foamboard design. Good stuff, Josh!
 

FAI-F1D

Free Flight Indoorist
#9
This is exciting! I won't be participating, but I will be sitting back munching on the popcorn. This is really going to push foamboard design. Good stuff, Josh!
C'mon, you know you wanna build one! ;)

If I can weigh in on my own question, I can see it two ways. Once you start doubling, tripling, otherwise thickening the skins on DTFB, and perhaps building fillets with paper, you end up building a cardboard/fiberboard plane. That's my excuse for "no".
I guess the question is whether laminated paper can exceed the strength to weight ratio of foamboard. My gut instinct is that it can't, unless you resort to fancy resins (hence the "no epoxy" rule).

It could get you strength that might even exceed carbon rod (which is a very specialist material..) So it's not a limiting factor.
Mmmm...doubtful. Carbon is a pretty amazing material. Paper...yeah, you can do cool things with it, but it'll never reach even half the strength to weight ratio of carbon. Only balsa can achieve that level of performance.

Are we going to be limited on adhesives? :)
See above. You can completely change the structural properties of foamboard and paper by using fancy resins. I'm thinking we limit ourselves to hot glue, gorilla glue (for those in wet climates), white glue, and perhaps polyurethanes.

Having said all of the above, I'm thinking we should try to limit the use of laminated paper just to maintain the spirit of the event. Paper fairings should be fair game though. FT now produces quite a few models which depend heavily on paper fairings, so I think it would be unfair to the overall concept to rule them out. Anyone else have an opinion?

Also, if this is going to happen, we really need to drum up some more interest. I'm probably going to draw something up regardless, but this really needs a good number of people participating to be an actual contest. So far my pleas on facebook for the people discussing it there to come over here have gone unanswered except for Nerdnic, who I'm really hoping will jump into this with his innovative work.
 

Mid7night

Jetman
Mentor
#10
I'm not ready to say "I'm IN", mostly because I think I've got enough projects in-work at the moment, and adding another is probably not a great idea for both my time and money budgets. ;)

However, I AM very intrigued by this and want to participate in some way....so are there any builders who would like to team with a designer? I love to create and model planes, but I'm limited in the physical space I have available to bring them out of the computer and into reality.
 

Nerobro

A Severe Lack of Sense
#11
My plan was to use white glue (as it's still flexible, and makes good use of the papers properties...) to do the laminating. :) We'll see what happens this week.