grant-RCU

My Feedback: (10)

I had to try my new fuel in the PAW 06 since the TT pro 46 dieselized wont hardly run on the fuel. The fuel consists of the cheapest brand of starting fluid from the convience store, kerosene from walmart it clear and havoline 20W 50 motor oil. Thats it.

25% motor oil
about 5% starting fluid I dont think its much ether in this kind

the rest kerosene.

The paw 06 ran well on this blend. I think i had to up the compression about 1 trun from the old english mix but it ran and it ran fine. The idle is higher and it will quit if it idles too low. Cetane booster might help. 1/4 to full throttle it runs great.

As I noted in the TT 46 thread the compression on the paw is high compared to the 46. I guess my 46 is on its last leg. The 46 was barley runnning on the same mix yesterday with varing rpms with the compression screw all the way down. it wouldnt run if i backed the compression out some. The paw is no where naer maxed out on compression and it hold a steady rpm. I didnt check it with a tach.

grant-RCU

My Feedback: (10)

More testing on the PAW .06 Since my test 6 days ago, I put the plane up with half a tank of fuel left in the tank and the vent line open. So i am 100% sure all the starting fluid evaporated out over 6 days. So now the fuel is straight kerosene and motor oil. mix is 28% oil and 71% kerosene. The engine fired up pretty easy considering no ether or cetane booster.

I used my 1/2a starter to start it. It takes a few full throttle burps before it will keep running. The needle is more touchy without ether but the compression doesnt vary except during a cold start. i think running compression is about 1/2 turn less from starting compression. I have a 8x5 or 4 prop cut down to 6 3/4 inches. The engine turned it in the 10K range full throttle and mid 4s for the idle. Anything lower and it would flame out However the plane flew well with the higher idle and the engine didnt miss a beat during flight.

Too bad my TT pro 46 will not run well on diesel. I may get a paw diesel in a 40 size.

What do you guys think of the rpm numbers?

Does anyone need a TT pro 46 davis head?

AMB

Grant are you sure about the numbers on the mix?? I am looking at the PAW factory sheet right now which lists the fuel mixes rather than list all the percentages it runs between
30 and 33% ether, kero between 35 to 50% the balance of of course castor oil and 2 to 3% ignition improver it is possible if model stored in cool place you did not lose the ether

the ignition improver if a nitrate cetane booster is not really prone to evaporation

It seems to me if PAW thought the engine would run on less ether they would state it in a high compression stock engine 20% ether is a possibilty . There is no way a davis conversion will run on 5% or less ether neither will a stock irvine 40 diesel nor stock MVVS. and quite sure many others your el cheapo engine starter spray can may have

more ether in it than you think If you have the "miracle PAW" I am sure they would like to know about it (PAW) martin

For a change of pace with the electric thing out there and some nice arfs built up some of the guys have gone to to glow and and sure a few diesels out there also
and Webra has just released a 91 sparker carb looks like a normal glow one they are saying 25-1 mix so I would guess a bushed rod with the new stuff coming
maybe some one will pop a diesel
Think the nostalgia or retro thing making a comeback whats next maybe a 60 ignition?? I still think OS will pop a diesel martin

grant-RCU

My Feedback: (10)

Yes i mixed the fuel myself. Its kerosene from Walmart and 20W 50 Havoline motor oil and starting fluid. The plane was in my trailer for 6 days with temps in the 80s. I didnt smell any ether in the exhaust either. I will mix another batch and see with no starting fluid and see.

AMB

Grant give it a shot sure everyone watching this one martin

grant-RCU

My Feedback: (10)

I just got in from testing a new batch of fuel.

Fuel is K-1 clean kerosese from Walmart its clear desulferized with 20W 50 havoline motor oil.
30% oil and70% kerosene.

I ran the engine on old english mix as well.
result of old english mix max rpm 10680 idle 6230rpm head temp 215 degreeas

results on no ether mix max rpm 10440 to 10560 idle 5600rpm temp 220 degrees.

1st I ran a 1/2 tank of old engilsh through the engine to get it hot. I ran the tank dry then I filled up the tank with the no ether fuel.

The compression had to be incresed by 5/8 of a turn to run without missing on the no ether fuel.

I did run it 1st on no ether but it was very hard to start so i set the engine on the old english and switched back to the no ether.

I really dont understand why it will idle lower on no ether fuel than the old english fuel. I checked the rpms and temp multiple times and it was consistant. I ran it about 1 hour on both fuels. The idle on no ether was smother with out the putt putt idle of the old english mix.

I am in awe over this finding.

grant-RCU

My Feedback: (10)

I just did another test after eating. The engine had cooled back down. It was hard to start. I had to keep the electric starter on it while firing until it was hot enough to run on its own. I also shot a few shots of starting fluid in the carb to help it get fired up. Idle was a tad higher this time in the low to mid 6K range. if it sits for a little the engine will get cool enough to make transitioning from idle to full throttle very hesitant as the engine has to warm back up. It seems like a 40 sized diesel would actually run a lot better than the .06 since it has more air to heat and it doesn’t lose heat as quickly as a small engine. I also had to increase the compression about ½ turn more to get it to fire cold but once running it was back where it was before 5/8 of a turn more from the compression setting for the old English mix.

Amsoil cetane booster may help as well at 5 to 10%

chevy43

My .061 PAW is doing 13,800 to 14k on a 7x3 MAS on my "Baker Black Brew" that is about 6% ether. Paw's have great compression and run better than other engines.

My best running engine is my OS LA .40 with the Davis head and it runs great on the "Baker Black Brew"

Treven.

grant-RCU

My Feedback: (10)

Treven,

Does the engine have a good idle on the BBB fuel? Mine will run fine 1/2 to full throttle on no ether but at idling it cools off and it has a bad throttle lag until it warms back up. It will quite idling if i let it sit too long. Hard to start on no ether also.

chevy43

It idles pretty well. It throttled up well but if you throttle down too fast it will quit so I always throttle down smoothly when I'm flying. IIRC 5k is a reliable idle and you can go slower but it will quit. It will hand start but it is not easy. Reliable starting requires a starter. I had to clean carbon off the top of the piston after many hours of running.

slope-soarer

Hi Grant,
Last year I did a fair amount of testing with homebrew diesel fuel.
After much messing about I found the best mix for my PAW 09 and .15 diesels used the following ingredients....
2.5% ignition improver
12.5% 10W40 engine oil
16% of modified olive oil
10% ether
8% castor oil.

The castor oil can be left out and replaced with more engine oil... I have it in my mix because I am diluting a commercial fuel mix which has 30% ether content and 24% castor oil in it.

The ether can be left out also and the mix will run well. Starting with low ether or no ether at all is easier if you prime the engine first with a normal high ether content fuel. A couple of short burst after priming through the carb will get the engine warm and make it easier to start. Pull fuel up to the carb, prime again with a couple of drops of high ether fuel and a quick spin on the starter should have it running O.K. Once it has properly warmed up then the correct compression setting can be found for best running.

The inclusion of modified olive oil in the fuel mix gives exceptionally good idle and transition.
I can leave the PAW .15 on a very low idle for 4 minutes at a time and it will transition straight up to full throttle without any "hiccups". Without the modified olive oil in the fuel mix the idle speed needs to be higher and is not quite as smooth and there is a slight hesitation when opening the throttle quickly after a long idle period.

The PAW engines I have run well on low ether mixes and also on non-ether fuel. I settled on the 10% ether mix last year as it gives easier starting. I want to do more running with non-ether mixes this year and will prime with high ether content fuel to get the engine started.

Modidfied olive oil is described somewhere in the non-ether posts, try page 4 but substitute olive oil for the vegetable cooking oil mentioned there.

NM2K

My Feedback: (14)

I'm not expert at this at all, but I would have looked around for a heavy viscosity single weight oil, Grant. That multi-vis stuff has me worried about your engine. Then again, one has to do what one has to do.

Does the converted TT .46 Pro have good compression?


Ed Cregger

gkamysz

My Feedback: (19)

The multi viscosity oil in our engine is not harmful. It's in the engine for a breif period of time and hardly ahs time to break down. And you are never operating at a low enough temperature to even think about the winter rating. The only concern might be all the additives. As was mentioned in the etherless thread the oil might have additives which inhibit combustion in our engines. It would be interesting to try an non-detergent oil to compare, even plain old castor.

How many turns out from hitting the piston are you? 5/8 turn in plus, an extra 1/2 turn to start seems like a lot when they say you can find the initial compression on a PAW by turning the contra in until it hits the piston, then backing off 1 turn.

merugo

Greg,
since the threads of contrapiston screws are generally the same, the right unwinding from the touch of the piston depends mainly on the stroke of the engine ,The rule is " unwind as many turns from the touch of the piston as the engine stroke (in inch) divided by 18 and multiplied by the contrapiston screw thread (turns per inch). Then try starting around this setting.
Slope soarer,
if you have additional contributions or notes about your mix, couldn't be useful to reedit your contribution to the fuels thread?
Presently I have begun to have some doubts about the true "modificatin" the olive oil has throug the suggested procedure. I guess all the thing is only a bleaching of it, that could be reached by simpler means.
Ugo

slope-soarer

Presently I have begun to have some doubts about the true "modificatin" the olive oil has throug the suggested procedure. I guess all the thing is only a bleaching of it, that could be reached by simpler means.
Ugo

---------------------------------------------------------------
Ugo,
I can't say if the process works or not. It was originally described by a bio-chemist and has since been supported by another bio-chemist.

I DO know that incorporating the modified olive oil in the fuel mix produces results. I haven't yet had the courage to use modified olive oil as the only lubricant in the fuel.Using the olive oil as well as a mineral oil or synthetic oil gives better idle and transition. The engine seems easier to start as well.

It could be that the modified olive oil is improving the piston/liner seal and giving better compression.... I don't know. But I DO know that there is an improvement when it is present.

merugo

Slope soarer,
I am not telling that olive oil does not work: I have used it with castor and it seems right: What I am saying it is that the "modification" does not seem to reach the alleged saturation , but simply a bleaching, removing the few possible gums, destroying the chlorophyll, and the tocopherol. This last effect is adverse to the stability of oil, that means shortening the time to use. For assessing the truth it has to be done a jodine test, but I am evermore convinced that simply bleaching by calcium hyposulphyde would make the job, if necessary. Maybe it is sufficient to leave the olive oil straight, since it has intrinsically by far less gums than castor. I will make another fresh batch and confront the viscosity with the straight oil.
Ugo

AMB

merugo your formula for setting the contra may be right for the PAWs and similar where the contra is in the cylinder , but does not apply to a contra in head design such as davis. irvine, MVVS 61. a newbie could find this confusing martin

merugo

Martin
if the contra is in the head and not in a the liner ( no more of 5% of "real" diesel engines can be so) they are two possibilities a) the contra does not touch the piston, in this case the formula cannot obviously be used, b) the contra touches the piston, in this case the formula can be applied, you have simply to take into account the bore reduction ratio between the engine bore and the head bore( if you have a conversion head it is easy to measure) and multiply the turns of the straight formula by the square of this. ratio. Then TRY starting from this setting
If you have another way use yours, but a newbye has to confront wth the too many possible turns of an usual contrapiston screw. Now I have no need of any formula, but unfortunately it was not so when more than fifty years ago I had a lonely confront with my new dyno, with miserable results.
Ugo

slope-soarer

>but I am evermore convinced that simply bleaching by calcium hyposulphyde would make the job, if >necessary. Maybe it is sufficient to leave the olive oil straight, since it has intrinsically by far less >gums than castor. I will make another fresh batch and confront the viscosity with the straight oil.
>Ugo

That would be an interesting comparison. If the olive oil was just as effective when used straight then it would save a bit of work in the kitchen !