Briggs and Stratton airplane

Well, my idea is to make a huge model airplane basicly and power it with this 1958 3hp briggs flathead which i've modified somewhat. Like a contol line plane that you contol with a cable. I was planning on welding up a fuselage out of 1/2" electrical conduit. I was thinking that maybe you guys would have some ideas on what to skin the wings with (or possibly a light wing structure). It would be nice to be able to paint it whatever color you want which kind of limits things like plastic sheeting. Everything needs to be as light as possible. I have to make up a wooden prop like frostypaws did with that honda gc160. Probably not quite as big of course.  Wooden prop

I've done some test running and the engine seems to cool good enough using the test propellor. Might need a different carb, seems to bleed in now and then.



Basic world war one biplane look I was thinking of. Sopwith camel.

Very interesting- especially thinking about the cooling. You could concieveably leave all the shrouds off, and have a machinist take the fins off the flywheel. It would free up a bit of power, and save some weight.

That '58 Briggs... Iron block? Perhaps aluminum would be a better choice for weight?

I recommend going to a diaphragm carb like a Tillotson, if you'rs isn't. I didn't get a good look. A bowl carb sn't a good choice for an engine that will be operating on various angles.

Wing skin... How about the heat shrink plastic they cover boats with?

Damn cool idea tho!

Maybe shipping wrap, clear plastic. I like the boat plastic tho.

Thunderdivine wrote:

cling film? not sure what the english word for it is,

Cling film is correct. Also called cling wrap, shrink wrap, etc. Marketed for food under brands like Saran Wrap. Commercial versions used for wrapping pallets for shipping, etc.

Something like that might work. I did cut the fins off the flywheel. Some is left because I cut them flush with the high spots so the ballance would stay equal and for looks. The engine is an aluminum block with a steel sleeve. I don't know if all of them were like that when they started with the aluminum blocks or if this was a heavy duty one. I think the last briggs model 5s was in 1957, so this is right at the begining of the aluminum engines. Come to think of it, maybe it's a 2 hp. The carb is a float type. It's a tillotson off of a continental red seal engine that was used on a quarter midget in the late 60's. That's why there's no choke plate, they removed it. I was thinking about how tipping it might mess things up a little. It might be workable somehow though because the plane will probably not see too much up and down angle, mostly just centrifugal force since you'll be flying it in a circle around you. I may be able to tip the carb slightly towards the inside to comprimise between idling on the ground and flying. I think aerobatics will pretty much be out of the question with this one. I'll be lucky if it leaves the ground.

Here's a video of a pretty good sized control line plane. Gives me some hope about the weight. You can see the guy flying it is leaning back against the line pretty good though. I was thinking maybe a bit of rudder permanently adjusted to the inside of the turn would help a little on mine.

Cut the threaded part off an old muffler to make the exhaust. Propellor hub is a v belt pulley from tractor supply with one half cut off. I'll probably use something similar for the wooden prop. It has a threaded hole in the end of the crank, so I put a safety bolt in so the hub isn't just relying on the set screw to hold it on.


Those carbs are somewhat strange. Float bowl is off to one side. Push mower flywheel, coil, and starter cup. I cut a notch in it for rope starting. I tried prop starting it, but you can't throw it fast enough to get good spark.


Intake was some push mower handle sections. Had to ding in the pipe a little to make it easier to get at that one flange bolt.

Before painting the manifolds. Push mower block that I stole most of the parts off of in the background.



Started bending up a little tubing. I guess the cowling will bolt to this hoop somehow. Probably another one behind the engine with a firewall of thin aluminum. I don't know exactly how this is going to turn out, looks kind of huge. We'll keep working on the fuselage anyway. Even if I don't complete the whole thing, it'll look good hanging from the ceiling somewhere.

This is different you don't see someone trying to build an airplane a lot lol, Goodluck to ya. Very interesting build.

I like the lawn mower blade as the propeller.

Thats dangerous having a blade as a propeller so don't put any limbs near that thing. Are you going to get a wooden one later on?

Yeah, I'm planning on making a wooden prop. Even though it used to be a lawn mower blade, I dulled the sharp edges on the grinder. Anything flying around like that with some weight to it is pretty dangerous, so I'm staying the heck away from it. Just having a bent piece of metal like this for a propellor isn't very efficent because with the thin edges, a lot more turbulence is created than a fatter prop with a tear drop shape to it. Even so, it still moves a decent amount of air. More than I expected. I'm kind of afraid of the wooden prop fracturing or something and flying apart. This wouldn't be that big of a deal if I'm just standing behind the engine test running it as long as no one else is nearby. But once I get the plane build (you know, if it ever gets done) then you would pretty much have to stand in line with the prop to use the thing. My idea is to keep it as short as I can so there isn't as much weight flying around and therefore less stress on the wood.

At least my setup is a little safer than prop starting the real thing. In this video the guy stays pretty close to the prop as the engine starts. Most other videos I have seen, the person turning it over walks off to the side while pulling it and gets clear whether it starts or not.

Craftsman1998 wrote:

Thats dangerous having a blade as a propeller

Ever seen a propeller that DOESN'T have blades? LMAO A wooden one won't F* you up much less if it hits you...

Bent up a couple sections of pipe and welded them at the back.



This is more or less what we're trying to end up with. The upper tubing will probably be under the exhaust instead of over it like in the picture.

Interesting idea cant wait to see hoe it unfolds

When I get a little more time I will get back to this project I hope. I was thinking the next time I run the engine I'll mix up some 2 stroke oil with the fuel for a little more smoke. I've gotta get my workshop organized a little so I have room to move things around.

I more or less gave up on the airplane idea due to other projects taking priority. So instead, I made a quick hack job test stand so I can run the thing once in a while without rigging up fuel lines and clamping it to a table. I welded up the hoop so I could still put a hood over the engine. Right now the crankshaft isn't centered with the hoop, I might file out the mounting holes and move the engine over. I actually forgot it needs to be lined up until after I welded the hoop to the test stand. No problem, we can fix that somehow. Could just leave it that way, but it looks a little strange. About an inch off.


I made the test stand fairly long so that I can fit a gas tank behind the engine and then i'll have an aluminum dash with throttle lever, shut off switch, and ignition blip switch. Also, you can add some weight back there somewhere so when your running wide open, it doesn't tip forward. Once I get everything put together I'll get some video footage again. This time in better quality and with more flames from the exhaust.

I like it. Can't wait to see the video.

Thanks. Just working on it here and there when I get a chance.

Some slow progress on the airplane engine. Decided other projects are top priority, so I figured I don't want to make the hood and cut the tubing back off the front. So now i'm just going to put some controls back behind the fuel tank. Started welding these pieces of rod together.


Gas tank from a 2 stroke lawn boy push mower. I was cleaning out a bunch of junk and actually had it thrown in the scrap pile. Then I figured this thing isn't gonna see much action anyway, so why use a better tank I could use for something else. It's a weird shape which is why I never used it for anything before. Fits pretty good in the rods I welded up.


Just a throttle and a shut off button, some paint.....fuel line and filter......then we should be good for another test run.

Forgot this was a thread, heres a video i shot of this in summer to add.

I guess an aluminum flywheel key isn't the best thing to hold that on. Good thing I had the safety bolt in the end of the crank. Seems like that phone picked up the sound better than my go pro did. Look at that high tech test stand!

Neat project here. Takes me back to high school, 20 something years ago, LOL. Got some tips for you. When you make the prop, a tear drop shape isn't quit right. You got to think airplane wing, which is what a propeller is, a spinning wing. With the flat side on the back side and the curved side in front so the low pressure your creating is in front sucking the air into the prop, and the low pressure also pulls the prop forward.

When making the propeller, a propeller is never made from a single piece of wood. A prop is made from multiple pieces of wood layered in a way that the grain of each layer is going in a different direction. This is done for strength.

That pic of that bi-plane used thin polyester cloth heat shrunk onto the frame, then dope was painted onto the cloth for sealing and to keep the air from passing through it. Yes it's actually called dope, kinda like fiberglass resin but will make your head spin in under a minute,LOL.

If interested, I still have my A&P class books. I can send you what I got on propellers and air frame skins.

Thanks for the info. I unfortunately gave up (at least for now) on the airplane itself, although I'm still messing with the engine of course. It would be neat to make a wooden prop at some point. Right now I got into some other projects and this one is down on the list of things to do.

Dude, that looks sick! Good job I have always wanted to make a plane...

the beast wrote:

Dude, that looks sick! Good job I have always wanted to make a plane...

Thanks! Still didn't get back to the actual plane idea, but I finally got the test stand done.
Throttle is 1950's era made by Briggs and Stratton. I was too lazy to drill holes to mount it, so I welded it directly to the test stand. Shut off switch bolts through a scrap piece of steel I welded to the gas tank support and is grounded to the test stand.


Carb end of the throttle is hooked up direct. Held in place on the frame with a piece of rubber hose and a couple hose clamps. Shut off wire is just run through a few convenient holes to keep it from getting into the flywheel. Fuel filter is for an air cooled vw beetle, but basicly the same as any mower/tractor gas filter.


Painted the 2 stroke lawn boy gas tank Detroit diesel green, but it fish eyed pretty bad in a lot of spots. I didn't have it cleaned off as good as I should have.


I ran it for a couple minutes, but vibration was worse than I remember. After shut down, I checked the prop hub and noticed the steel key I now have in place worked itself loose and almost slid out of the hub. So next thing to do is remove the propeller and check balance with the hub still bolted to it. Then I'll put it back on and try it again. Maybe try some glue or silicone on the hub/key also and see if that helps. I think if it was balanced better it wouldn't vibrate itself apart. Once it's ready to go, I'll get some good footage of it running close up in better quality than my old video. Think my old footage is only 480p and it was kind of dark also.