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Electronic solutions to modifying glow engines of all sizes to gasoline

Old 02-15-2023, 04:57 AM
  #1376  
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The tank drawn was a very quick one to "visualize" what's possible. My baffled Crap trap is of similar design but the vent is better located in it.. but I do agree a better design could be had.

The air pump will not suffer a regurgitation as it it very well "checked" on the outlet and that is not possible BUT... The bleed is in between the pump and the feed and that is the reason for the BT. The bleed will have an overboard drain (at the same level as carb inlet for proper uniflow operation


One nipple is pressure inlet one is needle valve adjusted bleed to overboard - outlet will be in "hopper" bottom (not printed yet). Print is "stringy" because of a bit of over extrusion for sealing.

Internal baffles

Gas compatibility verification .. 48 hours with no effect
Old 02-15-2023, 05:21 AM
  #1377  
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Originally Posted by Cat 1
The tank drawn was a very quick one to "visualize" what's possible. My baffled Crap trap is of similar design but the vent is better located in it.. but I do agree a better design could be had.

The air pump will not suffer a regurgitation as it it very well "checked" on the outlet and that is not possible BUT... The bleed is in between the pump and the feed and that is the reason for the BT. The bleed will have an overboard drain (at the same level as carb inlet for proper uniflow operation


One nipple is pressure inlet one is needle valve adjusted bleed to overboard - outlet will be in "hopper" bottom (not printed yet). Print is "stringy" because of a bit of over extrusion for sealing.

Internal baffles

Gas compatibility verification .. 48 hours with no effect
Perhaps a stupid question: is the fact that the thing is not printed in one piece because of technical reasons (the need to install stuff before closing up) or because of printing reasons (a complete tank cannot be printed in one run)?
Old 02-15-2023, 07:19 AM
  #1378  
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with planning, the tank could be printed as one piece (assuming it requires nothing added inside) i regularly print 2" bridges without supports. Gyroid infill is made to pass liquids so it could be used inside the tank if desired.

i'd like to print a tank from that material and see what pressure it holds without leaking. everyone online seems to think that 3d printed objects cannot be made waterproof without some sort of coating. i don't really believe them and it seems chris doesn't either. is that just standard PETG? who is the manufacturer?

also, well done, chris.
Old 02-15-2023, 04:37 PM
  #1379  
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Originally Posted by Raleighcopter
everyone online seems to think that 3d printed objects cannot be made waterproof without some sort of coating.
I would not know why not... I can totally see that printing temperature, layer thickness and "printer resolution) MIGHT lead to porosity, but logic dictates that selecting the proper values for those parameters should result in a liquid proof object...

But I could be wrong, because I know no more about 3D printing than what I can deduct based on only the principle and common sense. Zero practical knowledge with it.
Old 02-15-2023, 05:07 PM
  #1380  
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Dave is correct... I was just playing and left the bottom open to see how the inside printed - The combination of angles and some other methods could make it a one piece print..

https://filaments.ca/products/standa...rey-1-75mm-1kg. This is what I am using Dave - Its a House Brand PETG but I don't know where they would source it.. PETG can vary - I have some I got off Amazon and its crap too print with...

I am over extruding and printing at 260C so I really think its well sealed - at least 3 layer walls all round. It defiantly holds 2psi of air pressure from the pump with no apparent leakage and it held water on a test- I will print a closed cell and test with a pressure drop test..

I do have a little trick I was trying with the control line tanks - I have some Buna-N fuel tank slosh sealant that we use to seal aircraft Tanks - Its a clear red liquid that brushes on and air dries - Basically a thin coat of Buna-N (nitrile) rubber. Smells like death but works well.. I would not use this unless needed as its an extra messy and smelly step.
Old 02-16-2023, 08:28 PM
  #1381  
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Love how this project has these little "detours". I can confirm that 3D printed sealed vessels are possible as discussed. Air tight and fuel tight and fuel (mixed) resistant. Here are a few pics and a video of some of the fun...





Old 02-17-2023, 04:26 AM
  #1382  
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Is that just a tank for testing or is it a full barf bucket? Also, neato.
Old 02-17-2023, 05:13 AM
  #1383  
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Just a test tank - Will redraw the BT and make it a closed unit..
Old 02-17-2023, 08:27 AM
  #1384  
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so i guess we can also start printing crap traps (using clear petg, of course)


/me goes off to order a kilo of clear petg.
Old 02-20-2023, 07:29 PM
  #1385  
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SO .... I have a working unit... This is a BT for the Boxer install... fit much better than the aluminum one I made..

I did have a small issue - When I tested this one for Leaks (pressured up to 2 psi under water) I had a few tiny bubbles along a few of the corners - They were very tiny and I don't think they would have even leaked fluid as it held pressure well - None the less I came up with a trick..

I pulled a vacuum on the tank with the little air pump and gave it a quick spray with "plastic part prep spray". Its an aerosol can prep used to make paint stick better to plastic auto parts.. Its a thin clear coat with solvents that bite into most plastics a bit. Tank is now 100% leak proof..
I think the tiny "holes" are the result of the Layer starts - I will try playing with the settings to keep them from "lining up" or to add a little extra material on the layer change.

This part will make my install so much cleaner as lines and connections will be more organized.



Old 02-20-2023, 07:34 PM
  #1386  
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Very cool. So does the air pump mount directly to the barf tank?
Old 02-20-2023, 10:24 PM
  #1387  
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Originally Posted by Cat 1
SO .... I have a working unit... This is a BT for the Boxer install... fit much better than the aluminum one I made..

I did have a small issue - When I tested this one for Leaks (pressured up to 2 psi under water) I had a few tiny bubbles along a few of the corners - They were very tiny and I don't think they would have even leaked fluid as it held pressure well - None the less I came up with a trick..

I pulled a vacuum on the tank with the little air pump and gave it a quick spray with "plastic part prep spray". Its an aerosol can prep used to make paint stick better to plastic auto parts.. Its a thin clear coat with solvents that bite into most plastics a bit. Tank is now 100% leak proof..
I think the tiny "holes" are the result of the Layer starts - I will try playing with the settings to keep them from "lining up" or to add a little extra material on the layer change.

This part will make my install so much cleaner as lines and connections will be more organized.


That IS pretty!

Old 03-03-2023, 05:14 AM
  #1388  
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You guys still Kickin' out there??? Been slow here, but the Boxer mule is ready for covering.. Have the fuel system located and will install after covering.

I did print a "Trap" in Clear PETG and it worked well. Translucent and airtight - Can see contents and structure - Will take a few pics and send.

We are having issues here with Our Regulatory Body (Transport Canada) and our Federal Organization (MAAC) and it has us "grounded" right now but hopefully its sorted soon. Long story but Modellers up here are "very angry" but we are working through the process to get flying "legally" again. We went from having a "Cadillac" agreement and exemption for our flying , to a generic "everything is a drone" rule book because of a lack of oversight and some troublemaking and vindictive organization members. Most troubling.
Old 03-03-2023, 10:10 AM
  #1389  
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Yup, still kicking it here... Haven't been flying much because I am awaiting the "go" for me to get back on board again, so instead I spent a bit of time riding my old Duc... Friggin'cold, but the thing runs so nice since I redid the Weber carb last year, couldn't help myself.

Since this afternoon I learned that even in the extremest of cases I most likely will not join before monday evening late (VERY unlikely, because of the travelling distance I expect them to delay a day or two which will allow me to travel by rental car), so weather permitting, I will run the Boxer and a .52 (the Ogar motor-glider) on Sunday during an oldtimer/glider meet on Sunday.

Will be interesting as temperatures expected will be around 5 deg C and probably not too dry and sunny.
Old 03-04-2023, 05:28 AM
  #1390  
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Bert, (or others) - Have you ever played with a Webra 4 stroke conversion? I have run a lot of Webras and had a rotary 4 stroke back in the day but wondering how they would do on gas. One available up here..


Old 03-04-2023, 08:06 AM
  #1391  
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Originally Posted by Cat 1
Bert, (or others) - Have you ever played with a Webra 4 stroke conversion? I have run a lot of Webras and had a rotary 4 stroke back in the day but wondering how they would do on gas. One available up here..
Not sure about the T4-60 but I did run up a Webra T4-80 a couple of years ago for a club member. Very cool engine and collectable. The 80 is 1040 gr w/muffler and only 1.1 HP. For comparison the OS FS70 surpass is 595 gr w/muffler and also 1.1 HP. They both turn an APC 13x6 in the mid 10's.

Nostalgia conversion!

Last edited by Glowgeek; 03-04-2023 at 08:13 AM.
Old 03-04-2023, 09:06 AM
  #1392  
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I would be hesitant, for 2 reasons:

First: usually these type of fourstrokes have the glowplug "behind the valve" and a spark plug protrudes into the combustion chamber. It might interfere with the rotary valve. Even if it doesn't, there is the possibility of the wasted spark igniting whatever mixure there might be in a very tiny and confined space, which MIGHT cause issues over the long haul. Spark erosion on the sealing surface of the rotary valve also is a possible issue.

Second: I know conventional poppet exhaust valves can handle the heat because the lubricated part (the stem) is in a cooler part of the head. But I have no idea how the higher temperatures will affect the seal and bearing of the rotary valve. I know it should be possible because of there once were engines like the Napier slide valve engines and such, but I have no idea if the material selection of the Webra and for example the RCV or the HP fourstrokes is suitable. I never tried, anyway.

EDIT: A webra specific issue that just popped my mind: is the timing belt resistant to 2-stroke oil?
,
I have not the faintest clue whether these objections are justified or realistic, but I know they kept me from trying (I have a HP 25 fourstroke and the though had crossed my mind a while back)

Last edited by 1967brutus; 03-04-2023 at 09:08 AM.
Old 03-04-2023, 09:19 AM
  #1393  
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Webra had 2 types of rotary's and many versions - The first T4-80's (what I had previous and what Lonnie ran as I can tell by the weight) was a Aspin type rotary. This one and the smaller 40 (and the later 80's) were tube type rotary's and the plugs are not timed by the valve as they are in the Aspin type.

These later types are much simpler and lighter.. 600 ish grams for a .80 vs 1000 - Im working on a deal and might pick it up even if its not a candidate. Will have to study the valve construction.. I think its chromed brass in brass.






Old 03-04-2023, 07:36 PM
  #1394  
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Happenings today... Made a deal on the Webra.. Probably paid too much but very rare to see a good one up here. Will a have a close look when it gets here to see if we will try gas.

Got the Boxer Mule fuse covered... I hate covering but once I get started it goes OK... Colors were off the "bargin rack" at the local hobby shop - But I think they work...

Picture of the "clear" trap as promised - Put some water in it and can confirm level is easy to see even with water - Works well as a trap too. Didn't get a picture with fluid in it..






Old 03-05-2023, 08:20 AM
  #1395  
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Cool progress again, Chris! And yeah... those colours work... At least, they would for me.
Old 03-06-2023, 04:03 PM
  #1396  
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Default Asp ft160 modifying to gas

Hi to all..
my first time post,this thread is great to read and interesting..i have recently purchased a asp ft160 and have so far made a pickup/magnet ring from a piece of aluminialumin that i hacked and machined from a motorcycle top triple clamp..i like to utilise materials when possible!
I am waiting on the ignition system now..and i probably should get looking for a suitable magnet before the mail arrives..im now wondering what carburettor i should use..i have a saito fg21 and the carburettor fits on the ft160 manifold good.slight mod would have it mounted..i used this carb on the asp fs120 and ran perfectly....
you guys are doing some brilliant work on these engines
Old 03-06-2023, 04:31 PM
  #1397  
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Originally Posted by Rcplanedan
Hi to all..
my first time post,this thread is great to read and interesting..i have recently purchased a asp ft160 and have so far made a pickup/magnet ring from a piece of aluminialumin that i hacked and machined from a motorcycle top triple clamp..i like to utilise materials when possible!
I am waiting on the ignition system now..and i probably should get looking for a suitable magnet before the mail arrives..im now wondering what carburettor i should use..i have a saito fg21 and the carburettor fits on the ft160 manifold good.slight mod would have it mounted..i used this carb on the asp fs120 and ran perfectly....
you guys are doing some brilliant work on these engines
Hello Sir!!! Your project sounds like an interesting one - Will be neat to see how the FG21 carb will work. Keep us posted.

The 160 is a real sweetheart on gas - it has a very unique and realistic sound

Chris
Old 03-06-2023, 11:16 PM
  #1398  
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Originally Posted by Rcplanedan
im now wondering what carburettor i should use..i have a saito fg21 and the carburettor fits on the ft160 manifold good.slight mod would have it mounted..i used this carb on the asp fs120 and ran perfectly....
you guys are doing some brilliant work on these engines
Hi Dan! First of all, very welcome in our little club of stubborn engine modifiers.
Congrats on the purchase of the FT160, as Chris said, they are (or at the very least CAN BE) real sweethearts on gasoline, and those engines themselves are basically "without known issues" mechanically. Real gems in the rough: They do admittedly not look as nice as the OS they are derived from, but in every other aspect just as reliable, just as durable and just as userfriendly.

The carb for the FG21 is most likely a severe mismatch for the OS FT160.
In order to "match" a carb for a given engine, you have to look at the displacement per cylinder.
The FG has a cylinder volume of 21 cc per unit, The FS 120 has a cylinder volume of 20 cc, so that will work, BUT...the FT160 has a volume of 13 cc per unit. That leads to way too low air velocities in the carb intake in case of that FG21 carb being used on the FT160.
The cab for an FG14 would be a better fit.

Just as a fun fact example: The ASP FS80, FT 160 and AR400 all three use the same carb, because they alsl all three use the same cylinder units, and since in each of these engines there always is only ONE cylinder at a time in full induction stroke, absolute air velocity in the intake is the same, so they can function with the same carb. (Mind you, the radial will NOT work with a saito FG carb because there is not enough pressure variation in the intake to activate the pump since the induction periods partly overlap, so the radial basically has a constant intake flow).

Personally, I think the FG21 carb won't work properly (the engine will probably run but good settings will be VERY hard to find, if not impossible), but the FG14 carb should work, and I would expect it to work pretty good even.

Use a decent quality of oil (preferrably full synthetic, but there is really no need to go search for the ultimate exotics, nor is it critical), do not skimp on that oil: minimum is 20:1 ratio, but there are no real advantages (not technically, not financially, and also not WRT oil residue on the planerunning "as lean as possible"). On the contrary, the engine is real happy on 15:1 or even 10:1, and a fatter ratio has the advantage of not only keeping the engine cleaner internally, but also allowing to run a wider range of engines on the same mix.
Because chances are, you want to get rid of glow fuel alltogether. Something to think about.
Financially, it also is totally irrelevant, because of the very low fel consumption (on my yearly fuel bill the difference between 20:1 and 10:1 is about €7,-), and your Saito FG will handle 15:1 or even 10:1 without issues.

Last edited by 1967brutus; 03-06-2023 at 11:43 PM.
Old 03-07-2023, 12:55 AM
  #1399  
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Default Ft160

Originally Posted by 1967brutus
Hi Dan! First of all, very welcome in our little club of stubborn engine modifiers.
Congrats on the purchase of the FT160, as Chris said, they are (or at the very least CAN BE) real sweethearts on gasoline, and those engines themselves are basically "without known issues" mechanically. Real gems in the rough: They do admittedly not look as nice as the OS they are derived from, but in every other aspect just as reliable, just as durable and just as userfriendly.

The carb for the FG21 is most likely a severe mismatch for the OS FT160.
In order to "match" a carb for a given engine, you have to look at the displacement per cylinder.
The FG has a cylinder volume of 21 cc per unit, The FS 120 has a cylinder volume of 20 cc, so that will work, BUT...the FT160 has a volume of 13 cc per unit. That leads to way too low air velocities in the carb intake in case of that FG21 carb being used on the FT160.
The cab for an FG14 would be a better fit.

Just as a fun fact example: The ASP FS80, FT 160 and AR400 all three use the same carb, because they alsl all three use the same cylinder units, and since in each of these engines there always is only ONE cylinder at a time in full induction stroke, absolute air velocity in the intake is the same, so they can function with the same carb. (Mind you, the radial will NOT work with a saito FG carb because there is not enough pressure variation in the intake to activate the pump since the induction periods partly overlap, so the radial basically has a constant intake flow).

Personally, I think the FG21 carb won't work properly (the engine will probably run but good settings will be VERY hard to find, if not impossible), but the FG14 carb should work, and I would expect it to work pretty good even.

Use a decent quality of oil (preferrably full synthetic, but there is really no need to go search for the ultimate exotics, nor is it critical), do not skimp on that oil: minimum is 20:1 ratio, but there are no real advantages (not technically, not financially, and also not WRT oil residue on the planerunning "as lean as possible"). On the contrary, the engine is real happy on 15:1 or even 10:1, and a fatter ratio has the advantage of not only keeping the engine cleaner internally, but also allowing to run a wider range of engines on the same mix.
Because chances are, you want to get rid of glow fuel alltogether. Something to think about.
Financially, it also is totally irrelevant, because of the very low fel consumption (on my yearly fuel bill the difference between 20:1 and 10:1 is about 7,-), and your Saito FG will handle 15:1 or even 10:1 without issues.
hi brutus..
Thanks for the welcome..
Yes that makes perfect sense..now i think about it..like you say the fg14 carb would be more suited to the ft160. I have a fg33r3 i could pull that carb and do some testing with that..much closer fit for velocity..seeing thats 3x 11cc ..so alot closer..well its all fun and games with testing these things out i guess.. well i have another dream aswell right now ..i purchased a seagull models p26 peashooter 30cc ..now im looking to fit a saito fg60r3 in to that well its a perfect fit with room to spare..and maybe a touch heavier than most recommended engines for this airframe but should work out i hope....things to do while waiting for my ft160 ignition unit so i can bolt that thing to the bench
Old 03-07-2023, 03:07 AM
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Originally Posted by Rcplanedan
hi brutus..
Thanks for the welcome..
Yes that makes perfect sense..now i think about it..like you say the fg14 carb would be more suited to the ft160. I have a fg33r3 i could pull that carb and do some testing with that..much closer fit for velocity..seeing thats 3x 11cc ..so alot closer..well its all fun and games with testing these things out i guess.. well i have another dream aswell right now ..i purchased a seagull models p26 peashooter 30cc ..now im looking to fit a saito fg60r3 in to that well its a perfect fit with room to spare..and maybe a touch heavier than most recommended engines for this airframe but should work out i hope....things to do while waiting for my ft160 ignition unit so i can bolt that thing to the bench
I haven't checked, but I would not be surprised if the FG33R has the same carb as the FG14 (maybe modified attachment lugs or something like that) because indeed, 11 cc and 14 cc is fairly within acceptable range.

Personally, I'm no fan of the FGxxR series as they seem to require quite a bit of expensive modding from the box to run properly, and Saito seems not too willing to change their intake design. They ARE beautiful though, affordable, and the sound they make is amazing, no argument there

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