Aussie Damo

the plane would be a 1/2A version of the one in the pic but completely scratch built from drawings
its a bit of a crazy design and i was wondering if i should even start trying or is it just a waste of time

build light

Surely it would not be a waste of time. I think it would be a great model. just keep it as light as possible. This type of plane does not glide well under the best of conditions so one must do their best to do a power on type landing. It generally is a fairly fast flyer though not terribly fast due to the rather large frontal area. A poor flyer. By that I don't mean that it is hard to get it to fly, just that it is not a very satisfying plane in the air. A handful. keeps you pretty busy. To put it another way, it does not provide a relaxing flying experience nor does it lend itself to do aerobatics well. Still it will fly. Very cool plane though.
Not all planes fly great, some just fly.
I think you should do it! Just keep in mind the cool factor. Don't look for a fine performer.

Aussie Damo

thanks build light, that was the whole idea behind the project, the "cool factor"
i was thinking balsa frame with sheeting on certain areas for strength (guess i just have to try it)
havent decided between mixed controls ore elevator in middle and elevators on either side like some deltas
i also have to sort out the problem of cooling the engine
have no idea for span/length/cord, any ideas

BMatthews

It was done as a rubber model for P-nut scale so I don't see why one should not work for 1/2A. I don't remember where it was but if you could find the rubber model plan and then blow it up and just add in a few extra strips and cover it that would produce a nice light airframe.

BMatthews

Google "facetmobile" and got....

http://members.aol.com/slicklynne/facet.htm
http://www.currell.net/models/facet.htm
http://www.eam.net/EAMRC/skunkworks/...acetmobile.htm
and a heap of others.....

So it's obviously doable and quite flight friendly from the sounds of it.

And this version is pretty neat looking....

Aussie Damo

thanks for that BMatthews
looks like im going to have to build it now
i might start a build thread for it when i finish bipe's LST trainer

mgnostic

The fullsize aircraft was designed built and flown by Barnaby Wainfain. I think he also built a RC proof of concept model. He is a long time modeler and has a colum on aerodynamics in "Kitplanes" magazine.

combatpigg

My Feedback: (3)

That's a good photo of it. I say, take advantage of its' thickness and build it all open truss out of 3/16x3/16 balsa sticks and the lightest iron on you can get. If you build it as light as possible, then it should / could have very interesting flying qualities

Aussie Damo

thats what i thought combatt pig, i found a heap of stuff on the net, someone even makes a geared 280 electric kit of it using that method so it looks like a definite build at the moment, i even thought tissue paper to save wieght on the prototype even if it does rip easy. the CG will be tricky, do any of you guys use/ have some rule to find an approximate CG that you could let me know about

build light

A very interesting short article can be found here dated Jan 2005 so fairly recent. Has a great pic of a IC powered model.
http://www.eaa96.org/Newsletters/January2005.pdf

Aussie Damo

thanks BL, cant believe how much help im getting its great, again though does anyone have a rule for CG(sorry everybody for nagging)

Bipe Flyer

I think that this is exactly what the contest is all about. It gets you to build something that you might not otherwise consider. It also makes me wonder why I haven't tried something more unusual.

combatpigg

My Feedback: (3)

Depending on the aspect ratio of the delta, the CG formula doesn't always work like it should in real life. Just by looking at the photo, I would balance it just in front of the first contour line. Let me see if I can dig up my delta formula...........

MAC = 2/3 [ root chord + tip chord ] - [ RC x RT / RC + RT]

CG at 25% of MAC for starters.

Aussie Damo

thanks combat pig, by first contour do you mean red or blue
also, sorry for such a dumb question, what does MAC stand for

forgot to add photo

SGC

MAC=mean average chord
But looking at the 3veiw and the pic of the full sized framework pici I would guess the cg to be further forwards, about under the pilots bum or a tad forward ie:- between the thickest/highest section of the fuselarge and the exit point of the main undercarriage( it must be ahead of the mains at flying weight or it'll fall on its tail)
Stewart

Aussie Damo

Thanks stewart, one question since you live in australia, where do you get your engines from they seem so expensive here downunder

SGC

Damo, I purchased my last couple from Larry Driskill of "Kitting Together" https://ssl10.mysecureserver.com/kit...dex_store.html , his prices and service are great . You may need to email him and find out what hes got left, No more VA's are being made and he had only about 5 left, also Norvels are being dificult too,I think he has some 074 Norvels in stock(about A$100) , you may need to shop about.
Overseas online purchases are easy and postage from most decent dealers is not expensive, eg a VA049 +8 props and a few other little bits is costing me US$8 postage about A$11. As you have probably found 1/2a stuff is non excisting or very overpriced here.
Stewart

Aussie Damo

no kidding, a norvel in the states costs $35 while $110 here, its a joke
thanks for the posting tip, by dealers you mean tower hobbies etc
ive found heaps of stuff for the facetmobile, almost tempted to drop LST project and start on this, probably shouldnt though. Thanks for all your help

BMatthews

For the CG it's the same as a regular plank style flyingwing in that the wing area ahead of the CG must be less than 25 % of the total area. In effect a 25% center of gravit. But that figure would give you a very hard to handle flying wing or delta. Typically the area ahead is 18 to 20% of the total area and this gives you a stable model that will recover on it's own from a stall while a 25% CG will likely produce a model with very neutral and hard to trim pitch problems.

Figuring out the wing area of a multi break model is going to be a bit hard since some of the MAC (that's Mean Aerodynamic Chord) calculators sort of puke with delta wings in general and a multibreak one will be even worse. At least I've had mixed results but don't remember which were good and which were bad.

SGC has a great point about the CG having to at least be in front of the main gear of the real one. But for safety's sake I'd start with your CG maybe 2 or 3 % further forward than the upper apex line.

And Barnaby Wainfun was an avid free flight modeller so you KNOW this is a good design......

D Bronk

Here`s what I get nailed with ,price wise, in Canada..That price,on the package doesn`t include,the 14% taxes we get hit with here in MANITOBA,either.[:@]

combatpigg

My Feedback: (3)

As an eyeball guess, I would have the CG an inch ahead of the high point shown on that side view. A plane like that has alot of room to shift weight to the rear as needed. The other clue is the gear location, 10-20% of the models' weight should be on the nose gear and the balance on the mains. I think putting LG on this model would turn it into just another [yawn] mediocre performer though, where if built lightly enough, this thing could really be a crowd pleaser!

Aussie Damo

i dont plan to have gear on it to make it as slimline and light as possile
D Bronk, i now how you feel, prices like this make this hobbie hard to stay in if you live anywhere else apart from the USA, especially for a 17 year old like me.
started drawing up plans for framework from pictures of free flight models and the real thing

thanks for the tip on position of CG from LG location CombattPig
thanks to everyone else aswell

Bipe Flyer

Dave bought from the LHS and got burned $20 for the favour. I'm all for supporting the LHS if it is willing to be honest to me, otherwise I'll buy somewhere else. Mail order out of province reduces the taxes to 7% too.

There must be somewhere in Australia with decent prices on Norvels.

Aussie Damo

no and the last i heard was the importer (hobby warehouse) had only a few left in all of australia and wont be stocking up for a while. ill most likely purchase from the States now

Aussie Damo

thats why i choose this plane, it might give me a slim chance of beating you guys