chevy43

I'm flying a 17 OZ per ft. 32" span plane now. It flys pretty well now that I'm used to it.

I'm thinking about building even smaller planes with glow or diesel power.

For instance I'm thinking about a Wee Stick with a .033 PAW If I can build the whole thing and come in at 9 oz or so it should have a wing loading of 12-13 oz per ft. - less than what I'm flying now. Would it work? It seem like it should fly better than what I'm flying now....

I'm also thinking a really small mustang with a Wasp .061 would be really cool!

I'm thinking some SWR with wasps migh be neat too with 20" or less wing spans.

Whats the heaviest brick you have been able to fly?

Treven.

gkamysz

My Feedback: (19)

35oz on 170sq". But this was with 600W of power. 150MPH for 90 seconds, then it was a floater. I could land it at my feet everytime. Use a good airfoil. RG14 or 15. I've flow 16oz airplanes at 140sq" too. Back when Speed 400 was the craze there were pylon racers at 12oz on 80-90sq". These were tough to launch if you weren't good at it.

The thing to make sure is that your pitch speed is sigificantly higher than your stall speed, minimum 2:1 for an airplane that will be comfortable to fly.

ptulmer

My Feedback: (5)

Chevy, the neat thing about SWR's turned out to be the significantly lighter weight achieved. My Killer Buzz was 110 sq in, but weighed 9oz with a TD .049. The sheet wing provided decent enough lift to bring it in fairly softly. That's around 12oz/sq ft. 8oz or less AUW can be done, but is difficult without choosing your wood carefully. (or using your new lightweight battery!) So around 90 sq in. at 8oz, you would probably see the landings begin to seriously degrade.

FWIW, my PAW .033 is bigger and heavier than a Surestart and I can make the SS sing with a 4.2x4 prop. My choice would be a Killer Bee with that prop. We're talking serious speed issues, brother!

chevy43

OK! Looks like there are some fun options!

I'd like a cool looking 4 channel SWR about 20" wing span or so and about 100+ squares. 4 channel so I can ROG and land. It is really cool to see a small plane take off and land nicely. Is there a good P-51 in that size range?

There is a 24" Guillows P-51 that could be connverted......

Pat I'm going to do a search for your Killer Buzz.

Treven.

combatpigg

My Feedback: (3)

Chevy, I built a Mustang like you describe and it is my favorite 1/2A plane. I used the 24" Guillows plan as a guideline, but narrowed the fuselage as much as possible. It has 120 sq inches and weighs about 11 ozs. Oh ya...the wing is a solid sheet of 1/4" balsa with a full depth spruce spar that is about 3/16"x1/4"x12", and a little fiberglass in the middle 4 inches of the wing, IIRC.

chevy43

CP is it one of your racers? How much did you modify it? I wonder how it would work in stock outline? Did you go with the flat bottom wing?

combatpigg

My Feedback: (3)

Yes, it is a SWR. The wing is totally flat on the bottom and the high point of the airfoil is at the 40% chord line. For the fuselage I followed the outline in the side view, but made the fuselage the same width as the engines' backplate. At this size and weight, the 4.2x4 APC really works well, but you need to give the plane a good throw to get up to flying speed quickly. I also run the engine on bladder which allows hard launches without risking fuel starvation. Bladders don't foam up during the run, either. The control throws have to be very small, like 1/16" on the ailerons and about 1/8" on the elevator. The pivot for the clevis on the elevator control horn is about 1" from the surface of the flap. The fuselage is all sheet balsa, except I made the mistake of shaping the turtle deck out of foam.....would have been better off carving it out of light balsa and hollowing it out. To do a good job of scooping out areas like this, just jab a pin into the wood to gauge how thick the wood is in that area, and you can get a pretty uniform wall thickness. There should be a past build thread for this plane from a couple of years ago.

I say go for it! Build it!

ptulmer

My Feedback: (5)

Chevy, would you like to see the plan? My site is down, but I can email it to you.

combatpigg

My Feedback: (3)

I found the build thread. It is [modestly] titled, "COMBATPIGGS' CONTEST ENTRY". There is enough detail in that thread to give an idea about how simple these planes are to build. Might build another and put a REAL engine in it......

chevy43

Thanks PT I remeber it now. I think I might have even printed it. No need to email it to me right now.. It is a nice plane!

chevy43

Wow CP that Mustang racer is incredibly cool! That proves it can be done nicely! It might be easier for me to just build the guillows kit than to try to coppy that though. I'm really just looking to build a fun flying sporty plane - don't need to fly over 100 MPH!!!!

I keep getting different answers to what the wing span is on the Guillows mustang. Sometimes it is listed at 24" and sometimes 27". I'd like to know the wing area on it.

combatpigg

My Feedback: (3)

chevy, with the AP .061 up front and a 5x3 prop, that plane would do about 60 mph which is a nice cruising speed. I would build a 28" span SWR for your first go at it. Your appetite may get whetted for more after you build your first........remember that you can always play with wing area after the model gets built, just bring a knife to the field.

ptulmer

My Feedback: (5)

Save yourself some time. Before you mount an .061 on a guillows, just throw fifty bucks in the garbage and smack yourself in the head with a rubber mallet. The effect is similiar. Stick with your first instinct and explore the better aspects of SWRs. So far they've been used for high speed runs, but with the proper setup, you should have a good sport plane. There's still many aspects of the SWR's that haven't been tried.

combatpigg

My Feedback: (3)

I agree, the Guillows "job" should be reserved for a special time in your modelling life. Like right after you've been sentenced to serve 5-10 years in prison and your wife runs off with the mail man.

buzzard bait

Guillow kits are a great source for canopies, cowlings, and decals if you're building to the same scale, and many of them are practically free on ebay. The Guillow Mustang has a 27 inch span btw--the 109 is 24 inch--they are both scaled to 3/4 inch to the foot.

What's an SWR? Sheet Wing Racer? Must have missed something in this forum.

Jim

combatpigg

My Feedback: (3)

That's it, sheet wing racer. I went to the Guillows website once, it was funny to see them admit to having a checkered past with the modeling community. IIRC, they talked about improving the quality of their kits due to popular demand. It was a good website to browse.

rainedave

My Feedback: (1)

cp, your P-51 contest entry is amazing! That thread was before I knew about RCU. I think you should build a Supermarine Spiteful. It was one of the first (if not the first) British planes to use a laminar flow wing like the P-51. It would make a great SWR:

BMatthews

OK, I didn't read all of this but wingloading and speed are still enemys. Lots of speed lets you fly with a higher loading but higher loadings slow you down. The need to generate more lift results in more drag. This really shows up when you load up the wing in a turn.

Very light and symetrical or close to symetrical airfoils are the way to go. And SWR's? The flat airfoil works best with minimal angles of attack to ensure low drag. Again light is right on these.

As for landing and taking off the small size of wheels and small wheelbase kills the small models. But if you have a paved runway available then you can make small models with small wheels and they'll do fine. Otherwise you darn near need a golf green to land and take off.

combatpigg

My Feedback: (3)

Landing gear on a SWR? I always carry a pair of wire cutters in my back pocket, so don't even try it........

RD, that Supermarine job was even hotter than the P-51 by a slight margin, wasn't it? It's too much like the P-51 for me to want to build it, I want to branch out and try something different. Translated that means a project with a higher probability of failure.