P.A.W 35-DS running hard.
 

Hi
The Paw 35-DS is running hard. could you guys share me your views and experiences about this engine?

video link:

1) https://www.youtube.com/watch?v=F89_rFP2jbc


2) https://youtu.be/WVt_78mnKpc

fuel is home made

38% Paraffin
35% Either "Jone Dear"
25% Castroil
3% Ceton Boost "Amyle Nitrate"

:confused:

It is hard to tell from just a movie. First you need to secure the engine better, it seems to move in its attachment. Best thing is to get commercial fuel to get everything set up well, and only after that try with homemade fuel when you know how it should run and feel.

Yes, the motor board really needs to be bolted to something.

Otherwise, what prop are you using?

Motor seems undercompressed but dies when you increase it.

Could the liner have rotated in the crankcase so that the internal ports are masked?

Is the backplate loose?

Fuel looks a bit dodgy. The "John Deer" starting fluid may have an Ether content of between 60 to 100%.
Increasing it's component at the expense of the kero may help.

You say that you are using 3% Amyl Nitrate? It's a restricted substance in most places so you probably have DII, Amsoil or something else

3% may be too much but I'd guess that the ether is the problem..

Can you contact other diesel users in your part of Canada?

I have one of these and it's a big lump of an engine, rather crude c/w the TBR .15 versions, but predictable and easy to use.

First I am Thanking everyone who share the knowledge and help me to learn!

The engine is not new already braked in years ago. Yes in first video I had mound the engine in rubber mount. as it is seems it vibrate; in second video it is direct fit to wood plank, and concrete. It came off from concrete, so I was holding by hand. the Amyl nitrate from Amsoil ceton boost, in MSDS it says Amyl nitrate. In Canada up to my knowledge, I do not know any diesel fuel vender. the engine start very easily, Back plate and intake, cylinder head nuts are tight. I checked the liner in through inlet it seems not blocking.
I had tried more either like 40% Either, 35% Kerosene, 25% castroil, 2% booster.
and Ker40%,Eith30%,castr27% 3%booster and many other slightly modified proportions as well.
the Propeller I have tried APS 13x6 and Master air screw 11X8. the 11x8 is little better.
I have other P.A.W engines like PAW09 TBR, PAW100TBR, PAW249. all running well without a hitch.

The engine mounted well and solid on table the video link below.
https://youtu.be/JdlAe0BKGvI


http://www.rcuniverse.com/forum/atta...mentid=2109293http://www.rcuniverse.com/forum/atta...mentid=2109294http://www.rcuniverse.com/forum/atta...mentid=2109295http://www.rcuniverse.com/forum/atta...mentid=2109296http://www.rcuniverse.com/forum/atta...mentid=2109297http://www.rcuniverse.com/forum/atta...mentid=2109298

Just wondering if you have excessive carbon build up.

This thought is based on the engine not being new, it having a varied fuel diet and 'if' hot glowing carbon is present it could pre ignite the fuel mix outside of compression parameters.

Good catch there could be carbon in the engine. the engine is not used for over 30 years.it was not turning when I had it , Then I socked in diesel for over 2 to 3 days.

where should I clean the carbon? over the piston and contra piston is enough or should I remove the crank case as well?

I would suggest that someone more experienced than me guide you on this one - Ray ...... you there mate?

If that fuel works ok in your other PAWS then it's fine in this engine.

Those props are quite a way towards being an excessive load for my tastes. I use a Master 11" x 5" on my similar PAW 35 in a Ringmaster.

Can you trim your APS 13x6 down to say a 10.75" diameter?

Other than that I can't see too much wrong. Carbon on the piston might take a few 100's RPM off the top end of the range, but I don't think that it's your problem.

I have [h=3]Master Airscrew 10 x 8 Wood Propeller[/h][h=3]Master Airscrew 7 x 6 Propeller[/h]I will try 10 x 8 and post a video. 7 x 6 is too small I think. or I will buy 11" x 5" tomorrow.
when I sock the engine in diesel for release it to turn free I found considerable carbon particles in diesel. anyway first I try the prop then de carbonize the engine. It is definitely sputtering in run. the crank end play also to be minimize by washer.

Is any part of your fuel load above the jet in the spray bar?

Because from what I have just seen in the videos you have a control wedge tank mounted vertically and if it is full of fuel then the head will be above the jet.

This might cause the engine to sputter on a rich setting.

Check the PAW web site and it will tell you to never place any of the fuel load above the jet - perhaps this is the cause of the misfire?

I suggest in laying the tank flat and well under the spraybar and try again.

(And yes I have changed my log in details if anyone notices and will get Hobbsy to delete my old account.)

And I agree with the prop load being too high, the 11x8 is the recommended prop for the PAW 40 and a 11x5 should be much better.

Cheers.

Looking at the last video it seems to be under-compressed and too lean.

The tank is 3OZ 88 ml capacity I just filled 20 ml fuel. the fuel level is lower than jet "spray bar" level. and Controlliner "Member" advise that not to dismantle the engine. I agree the re mating will not be identical to the previous state of the surface. Is there any way to adjust the end floating the crank shaft propeller driver clearance? As when the engine run irregularly I hear shatter sound from shaft. I know for DS engine the play is normal for some extend. In this case I assume the play is too much. I am going to get 11X5 propeller today and let you know the result.

It could be under-compressed too in my next run I will tight the compression.

Thank you guys it is rocking now. Today it was a tight day for me, I went to Hobby centre 9.30 a.m around 25 miles away, the shop was close. Hear normally shops open at 9 - 10a.m . but he opens 11a.m. if I go back home my other schedules will sink me down, my wife always have a long list to keep me busy in all my vacations . every ideas you guys gave me is consuming my brain, so I decided to wait and finish the business. at last shop owner came at 11.15 a.m. the bad luck he had no stock of 11X5. I bought the closest one Master propeller 11x6.

at last my wife let alone around 6.00p.m in sympathy . I trim the propeller from 11x6 to 10.75x6 as "Qazimoto" said, yes I want to value any idea precisely.


hear is the prop before trim
http://www.rcuniverse.com/forum/atta...mentid=2109550


and the new batch fuel I made yesterday was ready to fire. this time I use 38 - 35 - 25 -2. 38% kerosene. and this time I use Amsoil cetane booster. before I was using Poler service cetane booster " it contain little anti gelling agent too, according to their label"



from this one to http://www.rcuniverse.com/forum/atta...mentid=2109551


to this onehttp://www.rcuniverse.com/forum/atta...mentid=2109552

here is the consequence !

http://www.rcuniverse.com/forum/atta...mentid=2109553
With trimmed propeller 10.75x6

video
1) https://youtu.be/qBDGQRRaou8

2) https://youtu.be/Yg-jEw5DUQM

I fill 20 ml fuel run out in less than 5 minuets run is it normal?
you guys are rocking :) thank you very much.

let me know if I can leave alone this end play or better to put a thin copper washer? ref video 2

It's good to hear it running so sweetly.

I have a few plain bearing PAW's and did shim the shaft endplay in the beginning, but eventually decided it wasn't worth the trouble.

PAW have been making them that way for decades and it doesn't do any damage that I've ever seen or heard about.

What a difference a fuel change can make! As for end float-PAWs have a lot-as do quite a few other UK made engines-it comes down to personal preference in the end. Some end float is essential in a plain bearing engine otherwise the engine would lock up as it warmed up and the crankcase expands faster than the crankshaft. How much end float is enough? Realistically about 5-10 thou. Many have a lot more than this-PAWs, DCs ED's and others. Other than being unsightly-it isn't really a problem as of course the thrust vector pulls the shaft forward when the engine is running-so its only an issue when starting-where excessive end float could potentially result in the crankpin contacting the inside face of the backplate (and very likely if someone uses an electric starter!)
If you want to reduce the end float by all means fit a copper washer though personally I'd use bronze or steel. The PAW prop driver is simply a friction fit on the crankshaft taper-so readily removed by simply inserting a thin screwdriver (preferably an 'instrument' type down one side between the case and the rear of the driver and giving it a gentle tap till the driver releases. You want the tapered blade of the screwdriver to act as a wedge-there is no need to try and lever the prop driver off with the screw driver. Needless to say the screwdriver should be a standard slot type-a philips or pozidrive one wont work in this situation!
Fit your washer, and replace prop driver, fitting a prop and tightening the prop up to assist it seating tight again. It would pay to 'face' the washer on both sides by rubbing it on fine W&D paper on a flat surface (piece of glass?) using a bit of oil to remove any burrs from the faces of the washer, lest these mark either the crankcase nose or the back of the prop driver.
www.modelfixings.co.uk do a nice range of stainless steel shim washers which may prove useful for this job (and probably better than soft copper.....)

ChrisM
'ffkiwi'

so I leave the end play intact. As you said In high rpm the prop pull forward and I do not hear any rattling noise.

So we don't quite know if the lighter propeller load or the new fuel batch actually solved the problem.

Can you give the PAW another run on the old prop with the new fuel and report back?

Hello I have already got the video with big prop first thing in the morning. no time to up load right away so I do now.

all the things you guys share me is valuable and I got some good studies from this ideas. first of all "Qazimoto" propeller suggestion put the paw 35 to closed to the peak bhp band around "12000rpm" with his suggestion the engine went up to 9233 RPM.

I really wanted to find out the answer for the same question you ask here is it prop or fuel. here is the video. in next post I will share my findings of fuel I tried since last month.

first propeller master air screw 10.75x6 reach upto 9230 RPM

engine stop as I close the needle

second propeller APS 13x8 reach up to 7100 RPM

engine stop as the fuel is empty

I will never quit guys I will go up to end ask me if I can do any other test

http://youtu.be/_g2TYlarL7E

This engine should be quite happy with an 11x6, 11x7 or 12x6. If you have any of these, I'd be interested to hear how it goes on them with your newer fuel.

Mine turns a 11 x 5 best. However it's a "tuned" version. It has a "T" stamped on one lug. Why? Well it's a long story. :-)

I do have 11x7 , 11x8, 12x6, 10x8. give me couple of days I will do the video. week ends I am going to fly morning 9 till 8 p.m. I will do this soon I can.

Sunday 37 Degree cel temp feel like 40, I thought not to go to field to fly. so I start videoing the prop range 10.75 x 6 to 13.8. After I fill the tank my friend call me to go to fly, So I am doing this clips in hurry.

let me know your views please so I may learn as well.


http://youtu.be/yjFDvfwyi40

http://www.rcuniverse.com/forum/atta...mentid=2110014http://www.rcuniverse.com/forum/atta...mentid=2110015http://www.rcuniverse.com/forum/atta...mentid=2110016

You can start by securing your fuel tank properly!............other than that it is running perfectly normally-and seems especially happy on the 12x5!

ffkiwi

Actually, on the 12x5 it seemed to go a bit hard (and/or hot) towards the end, and on all the props the revs were a little unsteady. I wonder if it could do with a bit more running-in, even though you mentioned it was run-in a while ago. Of course, it could just be down to the insecurity of the tank, and the mounting as a whole.