wannabebuilder

Hey,

Soon i will be starting to be a SAAB DRAKEN and a cessna 195.

I am new to the hobby but have built other models such as trainers etc.

I just wondered what would be a good size wingspan.

For the draken i plan to give it a 33" wingspan and the cessna 195 i plan to give a 40" wingspan. These were given to me in a rc planes chat room. However i want to double check they will be ok.



Thanks


Chris

Jim_McIntyre

Sounds reasonable. Are you building these from a kit? Plans?

Just my opinion but bigger flies better, especially with scale aircraft. No it's not a macho thing but, with the sizes you mentioned you may have a little difficulty flying from grass, especially when wet or not cut recently. Also, you'll probably have some difficulty with flying these in winds exceeding 15mph.

Do you have an engine in mind for this project? If cost is an issue, there have been some decent weedeater conversions that are quite reasonable. This also saves you money on fuel (gasoline is a lot cheaper than glow).

OTOH, smaller aircraft are much more convenient. I prefer to fly my larger aircraft but, if I only have a couple hours free, it''s the smaller aircraft that make it to the field.... it has to suit your lifestyle.

Just some thoughts, hope this helps.

BMatthews

You forgot to mention the engine size. Normally the wingarea is linked to the engine size and the span works out to whatever based on the aspect ratio.

But knowing these aircraft the sizes you're mentioning would indicate a very small engine like a Norvel 061 or a Max 10 or some such to me.

wannabebuilder

Hey,

Sorry i forgot to mention it was electric. I have been told to power it by a speed 400 motor 2:1 gear ratio.
The draken will be a Pusher ( then when i get better at fkying ill move up to a edf jet ).

The cessna will be a tractor (prop at front).


Well it would be good to have a smaller cessna if possible, but i got told they would be good sizes.


The draken ( because delta wing ) i got told it has to be big enough wingspan to fly, so they said 33" would be good.

Thanks

Chris

scalebldr

My Feedback: (7)

for that size electric motor the size sounds right just build light.but strong.choose wood carefully.

Tamecat

I have two ASP 91's. I am considering building either a huge twin trainer or one huge mother OV-10 Bronco. I was wondering what kind of wingspan will I be looking at with two 91 at the helm.

scalebldr

My Feedback: (7)

with two 91's it depends on the weight but somewhere in the 120 inch range.i have b-26 plans for 100 inch span for two 60's

BMatthews

Tamecat, I'm going to suggest the wing area again. But for your case I'd look at what monoplanes use for area with that engine and then consider a model with about 1.6 to 2.0 times as much for the twin. Which edge of the range depends on how light you think you can make it and what the model's flight mission is to be.

For example I've been contemplating a twin for a few years now (other projects keep getting in the way). I once had a Quickie 500 that I powered with an OS 25 FP and it flew very well at 3 1/2 lbs for sport flying. I figured that even if it was 5 1/2 to 6 lbs AUW it would still fly OK but not very aerobatically. So.... 500 sq in and 5 to 6 lbs. Double that and I have 1000 sq inches and max weight of 12 lbs with two FP's on board. Bearing in mind that this was to be a cargo type model with operating load options in a lighter airframe I figure that sounds about right. If this ever sees the light of day it's going to have a Selig 4233 airfoil for it's good lift, soft (I've heard) stalling charactaristics and thicker 12% wing section for more strength out of the spars.

For an aerobatic option with the same two engines I'd have a model of about 800 to 850 sq inches and I'd try to keep it to twice the Quickie weight for an AUW of 7 lbs or less.

So scout around for decent flying designs for your 91's and do the math. It would be interesting to hear what you come up with.

wannabebuilder

Hey,


Anyone know where i can get the airofoil for the saab draken wing ?

The guy who made it prevbiously then sent me the plans has not been online for a while now, think hes been busy making his b52.


I* was going to just copy his wings but i got told they need to have the right shape to fly etc.


Also i was wondering with that speed 400 6v motor, would it be able to take off ( from grounmd ) the cessna ? And the draken ?



Thanks


Chris

Tamecat

Hey Wannabebuilder,

Sorry for jumping in like that. It was either post here or make a new post. I hated the later idea since you were already asking the same question I wanted. As for your Draken project, That is an interesting idea and I'm sure you'll overcome any problems that will come up. Remember - PHOTOS please, PHOTOs