aero nut

Hey Bob do you think that if we replaced the thick gasket between the cylinder and the crankcase with manila folder paper to increase the compression on a Ryobi it would affect a lot the exhaust timing, maybe this increase of compression may help with keeping the plug a little bit hotter?

RysiuM

My Feedback: (1)

Not very much related here - or maybe it is: I tried my Poulan 25 on 50-50 mixture (gas methanol). This time the engine had magneto ignition. I couldn't start it by hand, but field started did as usually great job. I got maximum 7500 rpm on MA 16x8 Classic (the same load as APC 17x6), however the lowest stable idle was around 2000 rpm. basically it is the same result as with glow plug (but glow idle better).

I just got another Poulan 25cc to play with. Is any way to get a better power from it? Some hacking, sawing, drilling etc? Maybe bigger carb? I wonder if is any way I can get close to MVVS 1.6 what means 18x6W at 8200 rpm.

RysiuM

av8tor1977

My Feedback: (6)

In general, do the engines you guys have converted to glow hand start, or do they need a starter??

Thanks,
AV8TOR

RysiuM

My Feedback: (1)

I believe they must start by hand. I start by hand all my glow engines (from Norvel 0.061 to OS BGX 3500) with the exception of 4-stroke (Saito 30). All engine start using chicken stick except that for Norvel whee use bare finger (6 inch prop), and for BGX where I use haevy padded leather glove (18 inch prop).

if engine doesn't start it must be: bad glow or not getting fuel or bad compression.

With magneto the starter is often a must because magneto needs to run fast through the coil (like at 1000 rpm) to give a good spark. Glow engine lights always regardless of speed - the speed is needed for compression. On old engines (or very new not broken yet) the compression will leak through ring so thet's why you need to flip it fast. But if piston-cylinder seal is fine, fuel goes into combustion and glow shines red then the engine must start by hand.

RysiuM

Fishmasterdan

My Feedback: (2)

Av8tor;

Mine starts in 1 flip with the glow plug. I just need to prime it very good.

I picked up some 35% nitro that is straight mix with castor. I will see if it will blend with gas/methanol mix.

My math is very bad anybody have a ratio that would work?

I am thinking 5 ounces gas 5 ounces metanol 1 ounce 35% nitro/castor for a test.
That should be plenty of nitro and oil.

RysiuM

My Feedback: (1)

What kind of engine. The math is: 5 oz gas, 5 oz methanol, 0.35oz nitro, 0.65oz oil. = total 11 oz of fuel tha has:

5/11 = 45.5% gas,
5/11 = 45.5% methanol,
0.35/11 = 3.1% nitro
0.65/11 = 5.9% oil (like 1:17 oil: fuel mix)

if you are using gas conversion (with needle bearings on rod) you may reduce the oil content to 1/2. It would be:

10 oz gasoline, 10 oz methanol, 1 oz oil/nitro. This will result:

47.6% gas
47.6% methanol
1.7% nitro
3.1% oil (like 1:32 oil: fuel mix)

RysiuM

av8tor1977

My Feedback: (6)

Aeronut, sorry, missed your question. I think more compression will help. I don't use a base gasket on my engines. I use a sealer called Yamabond from the motorcycle shop. It's for crankcase halves on motorcycle engines that don't have a gasket. Works great. You can measure the compressed gasket thickness, and take that much off the top of the exhaust port to regain the exhaust timing. When doing this, you need to also check your deck clearance. (Piston to head clearance.) To do this, just insert a piece of rosin core electrical solder into the spark plug hole, and turn the engine over so that the piston crushes the solder flat against the cylinder head. Then measure the solder to get the deck clearance. You want about .016 minimum. Be sure the solder reaches all the way over against the cylinder wall, as many engines have a raised area in the head at the outer circumference called a "squish band". We often machine these out to be able to lower the cylinder as much as we want to, but most often you can get away with the "leave the gasket out" trick without having to do this.

Good luck,
AV8TOR

Fishmasterdan

My Feedback: (2)

RysiuM

Thanks for that. It is a needle bearing 45cc homey.
I will try and mix a blend up today. I have scratch built a 82 wing span profile for me homey. AUW is 14 lbs 3 ounces. I should be pulling at least 22 lbs thrust with a 20X8 at 7400 RPMs. That sould put me over the 1.5 power to weight and hopefully give me a fully capable 3d plane. Who says 3d with a conversion is not possible!!

We will see today (if the fog burns off) I will try and get some video.

Fishmasterdan

My Feedback: (2)

Ok;

My final experiment becasue I have a perfect transition and a VERY smooth low end idle. The high end is unchanged.

Motor;
Homey 45cc
glow to sparkplug adaptor
4 stroke glow plug powered all the time.
A walbro 499 carb (I believe cant remember the exact number but I can get it if anyone cares)
The fuel I used was 5 ounces methanol 5 ounces gasoline 3/4 of an ounce of 35% nitro/castor. The nitro I purchase was from the LHS and it was SIG champion fuel.

The test went.
Fueled up plane
Primed it about 6 flips (wide open throttle with my thumb over the carb)
Plugged in glow plug
1 flip backwards and it fired right up and ran.
I needed to lean the carb out on the high end.

Smooth transition and a great low end idle (I will try and get rpm data if the plane lives through the day)
The Nitro as mentioned many times help ALOT.

Edit;
I could not take it so I had to do RPM data
High end 7500 rpm
Low end it will idle down to 1500 pretty easy but I like it at 1850.

Good luck and have fun experimenting.

I found my methanol at a local speed shop for 2.85 a gallon.

aero nut

Hey fishmasterdan what do you mean by 35% Nitro/castor is it glow fuel with 35% nitro or is it 35%nitro with 65% castor oil? and where do you buy it? what is LHS? sorry for my ignorance!!!

RysiuM

My Feedback: (1)

Hey fishmasterdan if you used Sig 35% glow fuel (35% nitro, 18% castrol, rest is methanol) then you need a little more of that fuel in the mixtture.

1 oz Sig fuel + 5 oz methanol + 5 oz gasoline will give you:

45.5% gasoline,
49.7% methanol
1.6% oil (like 1:66)
3.2% nitro

better use 2 oz Sig fuel + 5 oz methanol + 5 oz gasoline will give you:


41.7% gasoline
49.5% methanol
3.0% oil (like 1:33)
5.8% nitro

RysiuM

av8tor1977

My Feedback: (6)

Ok, some fuel info, and something to try...

I mixed regular gasoline with E-85 half and half. To see if my oils were compatible, I then mixed one glass jar with this mixture and Pennzoil for Aircooled Motors, and another glass jar with the gas mixture and Amsoil Sabre. That was hours ago, and there is no sign of separation. I'm going to try this mix soon and I'll let you know how it runs. (For those not familiar, E-85 is available out of some gas stations, and is 85% Ethanol/15% gasoline.) It's about $0.50 a gallon cheaper than gas!

Second idea. I did some math, and here is something I want to try. (It will take me a while however as I live a loooong way from a hobby shop. If anyone would like to try this and let me know how it works I would appreciate it.)

Here goes: Morgan Fuels "Sidewinder Pro" model car fuel is 10% oil. I did some math, and here is what I propose:

Mix one gallon of this fuel in the 20% nitro version, with 3 gallons of regular gas and you will have the following mix...

5% Nitro
20% Methanol
40:1 Oil ratio

(Note that all numbers have been rounded off.)

I think this would be worth trying, but as I said it will take me a while to get to it. If someone else tries it, please let us know.

Thanks,
AV8TOR

RysiuM

My Feedback: (1)

Or beter get 1 gallon of nitro fuel, 2 gallons of gasoline and 1 gallon of clean methanol (replace one gallon of gasoline with methanol) and you will get the same oil and nitro but 50% gas and 42.5% methanol. Should give some extra kick

RysiuM

Fishmasterdan

My Feedback: (2)

" Hey fishmasterdan what do you mean by 35% Nitro/castor is it glow fuel with 35% nitro or is it 35%nitro with 65% castor oil? and where do you buy it? what is LHS? sorry for my ignorance!!!"


No problem. After reading the post it is pretty confusing.
I purchased some glow type fuel I think it was for cars. It was 35% nitro and 65% castor. I picked this particular brand because they used 100% pure nitro and pure castor (no other stuff to worry about).

I bought it from my LHS (local hobby shop).

I mixed 10 ounces of gas with 10 ounces of methanol then dumped in 2 ounces of the glow fuel (the 35%-65%)

I just got back from flying. All I can say is I have made a 3d monster with a conversion. WOO HOO
Plane weighs in around 14 lbs 4 ounces. Has tons of vertical. I will try and get some video tommorow.

av8tor1977

My Feedback: (6)

Hi,

I would rather keep the low fuel consumption and the ease of buying/mixing this fuel if the 20% methanol is sufficient to support glow combustion.

AV8TOR

Fishmasterdan

My Feedback: (2)

RysiuM :

The bottle didnt say methanol.
I guess I need to add a little more glow fuel in.

Thanks for that.
Dan

captinjohn

65% caster....seems like way too much lube???? Capt,n

RysiuM

My Feedback: (1)

I tried this idea on my Poulan 25cc. It already runs good and idles below 2000 rpm (without glow power) but I wanted to see what this 2% nitro can do for my engine.
So here is my mixture:

1 oz Sig fuel (18% oil, 15% nitro)
2 oz of mure methanol
3 oz pure gasoline.

The calculated result is:
50% gasoline
44.5% methanol,
2.5% nitro
3% oil (like 1:33)

Engine starts by hand but I need to flip the prop APC 17x6 backward, otherwise it starts in the wrong direction (like pusher). Because it is a pistton driven timing (side intake, sitde exhaust) the motor doesn't care which way to turn but I might loose the prop nut. Anyway, the maximum rpm didn't change however idle went well down to about 1500 rpm (glow not powered). But there is a one change I noticed: some kind of pinging sound. On mid and high rpm I heared some kind of high pitch pinging. It might be that engine fires to early. I'm affraid I can loose all bearing quite fast running the engine like that.

Then I thought maybe because of that I can get higher rpm on APC 16x4W. This time engine liked to start by flipping the prop forward. I still could hear this pinging noise and the engine could idle about 1500 rpm (glow not powered). The same as with bigger prop the maximum rpm was the same as on simple gas-methanol mixture. I had to lean the high end a little for this smaller prop.

I guess, I will not use nitro in my fuel as I don't know what the heck this pinging noise is about.

RysiuM

av8tor1977

My Feedback: (6)

You might try a colder glow plug. The other thing would be to add a thicker cylinder base gasket to lose some compression.

AV8TOR

RysiuM

My Feedback: (1)

It is pointless Why to modify the engine to run on fancy fuel if it already runs fine on 0% nitro methanol-gas mix. I wanted to test if adding some nitro I will get a better performance (read: more rpm), and I didn't. For Poulan 25cc 0% nitro works very well without any modification. I guess, for engines with not enough compression or problem with to cold plug adding nitro might help. But for my Poulan I will stay with $2.99 methanol and $2.65 gasoline (plus some castrol oil).

RysiuM

av8tor1977

My Feedback: (6)

Well, I'm thinking the sound you are hearing is probably detonation or preignition. When this happens, it is creating what we call "anti-torque" and limiting the power. If you raised the cylinder a bit, it would probably gain power for two reasons. You would be increasing the exhaust port timing a small amount, as well as defeating the detonation and therefore burning your mix more efficiently. Both should lead to a power increase, and you would still have the benefit of the lower idle and better idle response.

Just had another thought... Normally these small motors don't need high octane fuel, but this is a special case. I wonder if you used premium gas for your mix if this would help. Pretty easy to try...

Just my thoughts,
AV8TOR

Fishmasterdan

My Feedback: (2)

Mine wont run at all below 3000 rpm with the glow plug powered?? The idle is so rough at low rpms I had to add some nitro.

Mine motor is a chainsaw motor with higher compression. With that in mind I do think there is some pre ignition at lower rpms but it smooths out at higher rpms.
Mine like to run backwards. I have to flip the prop backwards to get it to start in the right direction.

I guess what I am trying to say is that it seems these conversion have a mind of there own.

If I were to start over I would just try 50/50 gas to methanol at 50 to 1 with castor or klotz oil. If the motor ran rough I would add some nitro in the form of glow fuel.

The best my motor ran was on straight 20% glow fuel but it makes a mess and is very expensive and I had to do carb mods.

RysiuM

My Feedback: (1)

Did you try to run it metganol-gas mixture with magneto ignition?

RysiuM

Fishmasterdan

My Feedback: (2)

No magneto runs.
The hole reason I started fooling around is the magneto was broke when I got it. I tried to fix it but it was to far gone. The fins were broke off and it had a crack in it.

av8tor1977

My Feedback: (6)

Hi,

Well, here's some results done with my hopped up Kioritz 23.6cc. I installed a new Fox glow plug, and ran my mixture of half regular gasoline and half E-85, mixed 40:1 with Pennzoil for Aircooled Motors. The motor gained a couple of hundred rpms over the electronic ignition/spark plug and pure gas setup, and idled much slower and smoother. It also hand started nicely, though occassionally in reverse. It would not however, run with the glow power turned off. When I turned the glow power off it would immediately begin to misfire, and then die. I'm guessing the ethanol, even at this percentage, doesn't have the catalytic reaction with the glow plug that methanol supports. Bummer, but the other gains are nice, as well as having less weight on board. I measured the amp draw of the glow plug with a good mulitmeter, and it is less than 1 amp. A 3000 mah on board battery should last a lot longer than I care to fly...

Another observation: It really does like to start much wetter than with the standard setup. I normally don't use chokes; just finger over the carb and flip 'till it gets wet, then fire her up. However, this setup likes to be so wet to start that I put the choke back in the carb. Then it's flip with the choke shut at low idle until it fires and quits. Then flip with half choke until it starts and once it warms up open the choke fully.

It will be interesting when I get a chance to try that mix I mentioned of 3:1 gasoline/Morgan Sidewinder model fuel!

AV8TOR