• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Balsa USA Bristol M-1 Kit

Which trim scheme should I do?


  • Total voters
    8

Ryan O.

Well-known member
#21
For the spinner, I'm not sure whether to put circular holes in the backplate, or to keep it a solid piece for strength. I don't think I'll need it, but if the motor comes back unusually hot after the first flight, I'll modify it since it is quick to model in Fusion.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#22
I just looked today, and saw a used Kalt K 20cc gas engine that looks ancient, but it is the right size :) Is that a good brand, and are there still replacement parts available for them? It is an auction, so it may end up having too high a price in the end, but hopefully the price stays low.
The carb looks like a Walbro, so no problem at all with a rebuild kit - that's usually around $7 or $8. I'd verify which Walbro carb part number it has, then order the rebuild kit for it (probably a K10-WAT or K20-WAT, which are fairly universal rebuild kits). For a couple bucks more you can "splurge" and get the Walbro tool used to set the metering lever. The carb spacer looks like my Zenoah G23, which is essentially what the engine is. I'd also buy new gaskets for the muffler and both sides of the carb block (usually about $3/ea). To be safe I usually just replace the carb block while it's all apart as cheap insurance. If the carb mounting bolts get over-tightened or too old they can get brittle and crack which creates an air leak. Carb blocks range from $3-10 depending on the model. A new plug will run $5-7 as well. So for around $25-30 you'll have all the common problems fixed and ready for a couple years of good times. :) When you pull the plug to inspect it, rotate the engine slowly and feel for anything "weird". About the only thing you should feel other than smooth rotation is maybe a slight clunk right at top-dead-center. Some of mine do that, some don't. I'm not sure if it's a sign of the engine being worn or just the way they work, but the engines just keep running without a problem.
 

Ryan O.

Well-known member
#24
There is also a brand new Evolution 20cc gas engine on ebay, but it is currently at $140 USD+$15 shipping, and the price is definitely going to go up. Plus, I'd have to break it in myself, which is something I have never done. What's your opinion on the evolution engines?
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#25
There is also a brand new Evolution 20cc gas engine on ebay, but it is currently at $140 USD+$15 shipping, and the price is definitely going to go up. Plus, I'd have to break it in myself, which is something I have never done. What's your opinion on the evolution engines?
It's a newer design, so it's lighter and maybe more responsive - it's got a better power-to-weight ratio, but you're not putting the engine on a 3D plane. It'd also have an electronic ignition, so you'd have an ignition module to deal with - I normally run the ignition on a separate battery pack so it doesn't drain the receiver/servo battery. An optical kill switch is almost mandatory as well, to kill the engine if you lose signal. A fail safe setup with a cheap 9 gram servo and reed switch will do the same with a magneto engine. The electronic ignition motors tend to fire up more easily than magneto, according to some, but if you're using a starter motor they both work great. Evo engines appear to be somewhat polarizing, people either love 'em or hate 'em. I've got an Evo 8cc with electronic ignition in a Telemaster Electro and it runs great. I haven't any experience with the bigger Evo engines.

The advantage with new is that it *should* fire up and run with minimal tuning or fuss. Probably. The disadvantage is that you'll want to break it in according to the manufacturer's recommendations. This can take a while, and in my case my wife isn't thrilled about me running a gas engine in the garage (with the door open) for extended periods of time due to the noise.

The advantage with the use engine is that it's probably already broken in (hopefully properly), but the disadvantage is that you'll want to rebuild the carb and replace gaskets so it's fully ready to go. If you're lucky the previous owner has recently done that and tuned the engine so it's ready to go, but people don't tend to sell engines they're currently using! :) The rebuild is fairly easy once you've done it a few times, but the tuning can be a little more tricky until you really dig in and learn how to adjust the carb. Once it's done, you may never have to re-tune it again.
 

Ryan O.

Well-known member
#26
It's a newer design, so it's lighter and maybe more responsive - it's got a better power-to-weight ratio, but you're not putting the engine on a 3D plane. It'd also have an electronic ignition, so you'd have an ignition module to deal with - I normally run the ignition on a separate battery pack so it doesn't drain the receiver/servo battery. An optical kill switch is almost mandatory as well, to kill the engine if you lose signal. A fail safe setup with a cheap 9 gram servo and reed switch will do the same with a magneto engine. The electronic ignition motors tend to fire up more easily than magneto, according to some, but if you're using a starter motor they both work great. Evo engines appear to be somewhat polarizing, people either love 'em or hate 'em. I've got an Evo 8cc with electronic ignition in a Telemaster Electro and it runs great. I haven't any experience with the bigger Evo engines.

The advantage with new is that it *should* fire up and run with minimal tuning or fuss. Probably. The disadvantage is that you'll want to break it in according to the manufacturer's recommendations. This can take a while, and in my case my wife isn't thrilled about me running a gas engine in the garage (with the door open) for extended periods of time due to the noise.

The advantage with the use engine is that it's probably already broken in (hopefully properly), but the disadvantage is that you'll want to rebuild the carb and replace gaskets so it's fully ready to go. If you're lucky the previous owner has recently done that and tuned the engine so it's ready to go, but people don't tend to sell engines they're currently using! :) The rebuild is fairly easy once you've done it a few times, but the tuning can be a little more tricky until you really dig in and learn how to adjust the carb. Once it's done, you may never have to re-tune it again.
I also found a used evolution 20cc that was run for about 3 hours. It is in good condition, but is 3 hours enough run time for breaking in? (and it may have been in the air). If I have to use an electronic ignition with the evo engine, and also need to use another flight pack, that might make up for the lighter weight than the Kalt 22cc, which is a good thing with this plane. There is also a DLE 20, but it is shipping from Pakistan, so shipping is likely going to cost quite a bit more than for the others, so I don't think I'm going to bid on that one.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#27
I also found a used evolution 20cc that was run for about 3 hours. It is in good condition, but is 3 hours enough run time for breaking in? (and it may have been in the air). If I have to use an electronic ignition with the evo engine, and also need to use another flight pack, that might make up for the lighter weight than the Kalt 22cc, which is a good thing with this plane. There is also a DLE 20, but it is shipping from Pakistan, so shipping is likely going to cost quite a bit more than for the others, so I don't think I'm going to bid on that one.
Some people do ALL their break-in in the air. On a new engine I often do a mix of getting it setup and running on the bench, then on the plane for more ground testing, and finally in the air after it's had a few tanks run through it. 3 hours could be just fine, but the safe bet would be to run it on the ground for at least a tank-full of good fuel to be sure.

Shipping from Pakistan? Maybe it's my paranoia kicking in, but that'd be a red flag for me if it's a private seller.
 

Ryan O.

Well-known member
#28
Some people do ALL their break-in in the air. On a new engine I often do a mix of getting it setup and running on the bench, then on the plane for more ground testing, and finally in the air after it's had a few tanks run through it. 3 hours could be just fine, but the safe bet would be to run it on the ground for at least a tank-full of good fuel to be sure.

Shipping from Pakistan? Maybe it's my paranoia kicking in, but that'd be a red flag for me if it's a private seller.
Luckily my field is pretty remote, so I could break it in there if I get that engine.
 

Ryan O.

Well-known member
#29
There are currently 3 engines which I am watching, so within two weeks I should hopefully be able to start building. The Cowl is longer than scale because it is made for 4 stroke engines, so I will likely have to trim it by a few inches. It is an ABS cowl, so it'll be easy to cut. I still don't have the Planetex or wheels because they are out of stock, but luckly those can be delayed until the later parts of the build.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
#30
Let me know if you pass on the Kalt, it'd be a nice addition to my collection of old school engines. :) I took delivery today on my Roush Mfg. Cobra 38cc engine (kind of a modified Zenoah, and it doesn't appear that it's related to Roush racing). I don't think it's ever been started and is in almost perfect condition for a 37-ish year old engine. It's old enough that it uses points and a condenser. :eek: At this time I have no plans to ever put gas into it, although I may check to see if it has spark. The tentative plan is to put an old prop and spinner on it, add a fuel line for looks, and make a stand for it so it can sit on my desk.
 

Ryan O.

Well-known member
#31
Let me know if you pass on the Kalt, it'd be a nice addition to my collection of old school engines. :) I took delivery today on my Roush Mfg. Cobra 38cc engine (kind of a modified Zenoah, and it doesn't appear that it's related to Roush racing). I don't think it's ever been started and is in almost perfect condition for a 37-ish year old engine. It's old enough that it uses points and a condenser. :eek: At this time I have no plans to ever put gas into it, although I may check to see if it has spark. The tentative plan is to put an old prop and spinner on it, add a fuel line for looks, and make a stand for it so it can sit on my desk.
I plan to go for one of the evolutions unless they go beyond my price range.
 

Ryan O.

Well-known member
#38
The other Evo engine still hasn't been bid on, which is good. There is also an OS 20cc engine, but it looks like it's going to end up costing quite a bit. For the Evo engine, I've seen a few people who put in an OS glow plug and were able to run it just fine. Would that work, and what are the downsides? It is less complex, but if it is prone to failiure, I'll go with the electronic ignition.

Now about the actual plane. The wing is undercambered, and I'm using shims to keep it with the right undercamber. The tricky part is that the Trailing edge, which is one piece of Balsa, has to curve slightly, so to make sure it gets the proper shapen I'm weighing everything down in place to 2 days, whichis okay because the next step requires a wood plane, which should arrive before then given there are no delays. About the "window" in the wing, since the Bristol M.1c had poor visibility, they cut out the fabric covering between two ribs. the kit has the scale rib and spar locations, so I'll be able to do the scale windows without reducing the structural integrity of the wing. What do you think I should name the pilot? I couldn't figure out who the pilot who flew the full scale one I'm basing the livery off of was, so I may just go with Nigel 😅
F2960A1D-82F9-49FA-8B4D-E7DBD27C5EE2.jpeg

EDIT it turns out this one was a trainer without a deaignated pilot. I can still name the pilot bust Nigel though, and give him a little name tag.
 
Last edited:

Ryan O.

Well-known member
#39
Sure, that works for you guys with the smelly noise makers up front - those are super heavy already! :ROFLMAO::ROFLMAO: Us electrocuters would need an ATV battery up front to balance out! :ROFLMAO::ROFLMAO:
Joe from Balsa USA said they are currently working on an electric motor mount that is adjustable for all their 1/6 scale planes. The cowl is already longer than scale because it is made to allow for a four stroke glow, so if you build the motor mount as long as possible and put the batteries on it, you may be able to balance it out. even with that, you may still have to extend the nose a little bit.
 

Ryan O.

Well-known member
#40
I also found a good 3d printed Pilot model I can scale to 1/6 scale and print with my tiny 0.25mm nozzle at 0.05mm layer height and then sand it for the most possible detail.. I can also add a tiny scarf to it. Also, for weighing down the individual parts of the wings I find it easiest to use hockey pucks with full water bottles on top. The hockey pucks make sure that the wood itself isn't damaged, and that every part is weighed down evenly. I also trimmed and colored the dummy propeller for the electric generator
image.jpg
image.jpg

https://www.thingiverse.com/thing:1750200
P.S. I'm thinking of making the pilot removable that way I can install a snoopy pilot when I don't care about the scale as much.