Briggs and Stratton airplane

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.

with what you are trying to do, I would consider trying to balance the blade, if the vibrations worse, something changed, airplane blades are ridiculously balanced if I recall, this kind of flailing speed demands it to keep the system working right. may be able to balance at home on a piece of round bar and measure your centers, or if the center hole is round, a bolt that fits as perfectly as possible and see if it spins over when level, if it does you need to lighten the heavy side, if I recall its usually taken from the back edge of the blade. hope this helps, will also help the motor not destroy itself from such a heavy flywheel if its way out of balance

I have one of those lawn mower blade balancing cone type things. It has a pin with an upside down cone on it. You can get them at home depot/lowes ect. I thought I checked it on that before, but maybe not. I don't really remember. It can't really shift much on the hub, the center hole fits over the hub pretty snug. Who knows. Not too big of an issue, I'll get it fixed up. It could be that it was always off that much and I never noticed because I had the engine clamped down better.

Yah, prop class was a good 10 weeks. To balance an aircraft propeller is real simple. 2 horizontal straight bars in a sealed room with nothing moving. The prop will have a rod going through the center and snugged up on it. Then placed on the bars and static balanced by the blades being vertical axes. Pretty simple. The mower blade balancers work OK but are on the wrong axes.

I found out both blades are bent somewhat to one side. Must have both went that way slightly when I twisted them. It would take a lot of removed material to make up for it, so I might as well just junk the steel temporary blade and work on a wooden one. I put it back on after checking the balance again and ran it for a short time. One of the set screws for the hub worked it's way out and apparently hit the prop which threw it back at me, hitting my pants. At the same time it started to rattle, so I shut it down. Both bolts that hold the prop to the hub had also came loose. The vibration loosens up everything. I guess I might have to either reconfigure this hub for a wooden prop or make a new one. Shouldn't be too big of a deal. It'll probably be awhile now anyway before I get back to it again.

I found a wooden prop for sale at a swap meet. It was $40 but it's pretty nice and it's fairly short. It was supposedly a salesman's sample. Hopefully it won't blow apart or anything, but it looks like it's made pretty well. I would need to make a new hub to fit it on the engine and also my test stand wouldn't be tall enough to clear it.


It has some numbers on it and also it's stamped "Not Airworthy" on both sides top and bottom. Looks pretty professional, FAA approved or not. I imagine you could look up those numbers, they must designate something.


I've been looking for a small one for a long time but I have only seen a few, not sure if I ever saw one this short before. I guess I could have just looked online and found something but that's cheating.

Pretty cool mr.mod, should look neat on there. You think it'll still cool the engine pretty good?

Probably not air worthy because there isn't any metal shielding on the leading edge of the blades. Suppose to have it for balancing and protection from debree. Should have the right shape though for it to work right. Which is a shape of a wing with the curved side facing forward.

Don't know, maybe. I have seen them without metal before though. Aerodynamic stuff gets complicated.

I've been looking at some ultralights online recently and saw some stuff about the legal eagle, which is basicly a real airplane which just barely makes the weight requirement's of an ultralight. All that metal structure made me think maybe I should finish building a small plane for this engine after all and give it a try. Worst thing that could happen is it won't work and I have a cool looking thing to hang from the ceiling. That or I get hit by a flying metal and or wood propeller.

That's cool!! We had an old bi plane in shop class that the teachers was trying to put a motor on so they can just taxi it on the runway. It was yellow, lol.

Very cool project.

Allow me to suggest you fuselage cover material: Dacron

It is the modern version of the vintage "Dope and Fabric" or years gone by.

Dacron is inexpensive, as you do not need the FAA Certified version.
Aircraft Spruce sells it for around $4.50 a yard:

(i'm to new to post a link, so Google Dacron Fabric and Aircraft Spruce, it will pop up)

It also happens to be what I used to cover the body on my CycleKart Project, which also uses 1/2" EMT Conduit tubing as the frame work.

This stuff is VERY easy to work with, you can use water based glue to glue it to the frame work, then use a cloths iron to shrink it tight.

Then you paint it.

Good luck with this project, I think it would be cool as hell

mr.modified wrote:

Don't know, maybe. I have seen them without metal before though. Aerodynamic stuff gets complicated.

I've been looking at some ultralights online recently and saw some stuff about the legal eagle, which is basicly a real airplane which just barely makes the weight requirement's of an ultralight.

That thing is running a 1/2 Volkswagen engine as well...

I have stumbled across a aircraft project, I believe from Europe, where the guy used a Briggs and Stratton Vanguard V-Twin powerplant