SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jul 01, 2010, 03:53 AM
Registered User
Joined Aug 2007
1,436 Posts
Diesel fuel tank , whats the go

Its pretty important that you get a consistant run out of the tank , Im setting up a wedge type tank with the uniflow vent about half way , maybe a little bias towards the back of the tank , is this regarded as the best setup , I suppose so ?

I dont like to use a plastic tank with a moveable clunk in its ,its not quite vintage controline looking
I think one of the things that kills good tank feed to the engine is engine vibration
NX-687 is offline Find More Posts by NX-687
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 01, 2010, 03:07 PM
Registered User
Canada, ON, Hamilton
Joined Oct 2005
2,633 Posts
Talking about bushed rods only being on the more expensive engines, here's an old Enya .09, regular plain jane, no BB and no muffler. But, this engine does have a bushed lower end . The crank pin or the rod end is slightly bent and the engine binds when the front end screws are tightened up; left loose on the front end, no binding, so it doesn't take much.

Wedge fuel tank works best for U/C. I use to use two vents, each to the other side of the tank. I flew with the top vent capped off. Vibration caused foaming in a ridge tank. Balance the prop. A smaller venturi will improve fuel suction, or a small 1/8 th inch tube could be used to direct muffler pressure, but for a diesel that shouldn't be needed.
JohnAV8R is offline Find More Posts by JohnAV8R
Reply With Quote
Old Jul 01, 2010, 10:49 PM
Registered User
TLyttle's Avatar
Keremeos, BC Canada
Joined Mar 2004
2,639 Posts
Try a thicker gasket on the front end, that may cure the bind when the bolts are tightened up.

I have yet to see a diesel run right on a glow carb, always has to do with fuel draw: the smaller the venturi, the better draw in my experience.

If one has access to a variety of metal tanks, the best fuel draw will come from a chicken-hopper tank. If you build your own, there will be no problem doing that. I, too, haven't had much success with plastic, clunk-type tanks...
TLyttle is offline Find More Posts by TLyttle
Reply With Quote
Old Jul 02, 2010, 03:04 AM
Registered User
Gluehand's Avatar
The windy west coast of Sweden
Joined Sep 2008
2,974 Posts
Quote:
Originally Posted by TLyttle View Post
I have yet to see a diesel run right on a glow carb, always has to do with fuel draw: the smaller the venturi, the better draw in my experience...
This is very true.....and, provided that you don't chase for top rpm's, you'll be surprised just how small a venturi a diesel will accept, with improved fuel suction and throttling properties....
On some carbs, you could just restrict the max throttle opening to acheive this. However a "cleaner" way of doing it, would be to insert a restrictor bush into the throttle drum, or simply shift to a smaller carb.....at occations I have tried all three methods with good results.

A 5cc (.29) diesel will do fine on a .09 size (glow) carb, or even smaller....

-----------------------------------------

Quote:
Originally Posted by TLyttle View Post
If one has access to a variety of metal tanks, the best fuel draw will come from a chicken-hopper tank. If you build your own, there will be no problem doing that. I, too, haven't had much success with plastic, clunk-type tanks...
In order to keep it simple, I use to avoid clunks too....for smaller RC, I prefer to use varoius standard C/L tanks if possible, though I have also made several tanks by modifying Colman's Mustard tins, etc...
I normally put the end of the pickup tube at the "bottom/rear" of the tank....

This setup obviously doesn't allow any prolonged inverted flight, but that is really the only limitation...

We may also consider that diesels have a very low fuel consumption, i.e. there's no need for a particularily large tank....
(My 1cc M.E. Heron runs 6 minutes on 10cc fuel, at full rpm with a 7x4 Master Airscrew)

Gluehand is online now Find More Posts by Gluehand
Last edited by Gluehand; Jul 02, 2010 at 03:15 AM.
Reply With Quote
Old Jul 02, 2010, 04:00 AM
Registered User
Joined Aug 2007
1,436 Posts
John

Quote:
Originally Posted by JohnAV8R View Post
Great suggestions for getting the head bolt out; perhaps better that way than before I break it off. I'll try soaking with oil for awhile, more heat, soothing curses, and whatever it takes. Here are a few pictures of what I am using, and where the problem bolt is, right in front of the exhaust.
You can buy an allen key that is high speed steel and has a largish handgrip, you choose a slightly larger size, eg , the next size up in imperial , then using an offhand grinder resharpen the hex to a taper that locks into your damaged screw head , I think that heat will help too , good luck
NX-687 is offline Find More Posts by NX-687
Reply With Quote
Old Jul 02, 2010, 07:39 AM
Registered User
stegla's Avatar
Guernsey
Joined Jan 2002
1,300 Posts
Hey Guys, Can anyone recommend a 2.5cc diesel for freeflight use. Robust, easy to handle and swing a big prop etc.........

Steve
stegla is online now Find More Posts by stegla
Reply With Quote
Old Jul 02, 2010, 08:05 AM
Registered User
Gluehand's Avatar
The windy west coast of Sweden
Joined Sep 2008
2,974 Posts
Thinking of a new one...?...I would strongly consider a PAW 15 DS....good value/fun for money at GBP 52.00....plus all spares quickly available etc etc...
Check at http://www.eifflaender.com/ I would prefer this one before a Chinese diesel any day....

..or, among the "classics":
Should you find an AM25 (not AE), this would be a good choice...practical and virtually indestructable...or, should one of the old Webra diesels (any type) come your way...just grab it..!...They are all top quality...

...I stop here, allowing some space for more suggestions....
Gluehand is online now Find More Posts by Gluehand
Reply With Quote
Old Jul 02, 2010, 09:02 AM
Registered User
QLD, Australia
Joined Sep 2003
1,551 Posts
Steve,
Consider also the New Parra 2.5 :- http://www.clubtamaran.com/parramotorING.htm
for sports use with larger props the steel cylinder version would be fine. they quote APC 10x4 @ 10,300 RPM which isnt shabby, its a modern twin ballraced diesel with optional extras available - ie different venturies,R/C carby, combat or regular muffler, can also be used as glow with one of the optional glow heads.
Stewart
clipclop is offline Find More Posts by clipclop
Reply With Quote
Old Jul 02, 2010, 11:04 AM
Registered User
stegla's Avatar
Guernsey
Joined Jan 2002
1,300 Posts
Gluehand and Stewart............. thanks for the suggestions. The Parra looks nice but the Paw should be good enough.

It's for a heavily built j60

Steve
stegla is online now Find More Posts by stegla
Reply With Quote
Old Jul 02, 2010, 11:58 AM
Voices through wires? Ha!
Chas's Avatar
Joined Feb 2003
1,659 Posts
John
In extremis you could drill a small pilot hole laterally through that exhaust port stanchion to access the naughty threads and free up the bolt, then maybe have to tap for a larger size bolt after disassembly; but it's fraught, innit?

On PAW's website they say that internal cleaning for carbon buildup should never be necessary, that these diesels are "self-cleaning". Yet they recommend Castor, and your experience would indicate that "crud" does indeed build up as a result (even if in storage). And he exclaimed, and rose up, and fled out of the land of the Castor-ites, unto the Valley of the Cinn-thettiks, and he saw that it was good.

"No matter how much care is taken, however, the dismantling of mated parts invariably results in some degree of re-mating and consequent wear, and it is therefore never advisable, and should be done only when absolutely necessary. NEVER dismantle an engine in order to "decarbonise" it. Excess carbon is ejected by the engine automatically as it accumulates. ". So, if it ain't the carbon, and it ain't an accumulated ether build-up, the crud is the Castor Oil. QED.

PS -I have several Enya 09's, plain venturi and RC, and I love 'em! If they convert well to diesel I'll have another evil project looming...
Chas is offline Find More Posts by Chas
Last edited by Chas; Jul 02, 2010 at 12:16 PM.
Reply With Quote
Old Jul 02, 2010, 05:41 PM
Registered User
Northumberland, England
Joined Jan 2007
640 Posts
Quote:
Originally Posted by TLyttle View Post
I have yet to see a diesel run right on a glow carb, always has to do with fuel draw: the smaller the venturi, the better draw in my experience.
I used the carbs from a pair of old type Thunder Tiger 20s (the OS Max copy ones) in diesels. One on a Silver Swallow 2.5c in place of the supplied insert the other on a PAW 19 that had lost it's own carb due to it vibrating loose in flight. Both worked perfectly. Easy starting & good throttle response, the PAW was better than with the original crude effort supplied with the engine
patmcc is offline Find More Posts by patmcc
Reply With Quote
Old Jul 02, 2010, 06:01 PM
Registered User
Northumberland, England
Joined Jan 2007
640 Posts
JohnAV8R, I once had similar immovable head screws on a Merco 61. It had Phillips head screws that had been chewed up. I managed to loosen all but one of the long ones. So I ended up cutting it with a junior hacksaw blade between the cooling fins. This meant I was able to remove the cylinder & fins etc leaving the cut screw accessible to mole grips. It then came out quite easily. The next problem was that I had difficulty identifying & locating the right size replacement screws. In the end I drilled out the 6 existing holes, tapped them 4BA & used allan studs. I later discovered that the originals were 1/8" Whitworth.
patmcc is offline Find More Posts by patmcc
Reply With Quote
Old Jul 02, 2010, 09:54 PM
Registered User
Joined Aug 2007
1,436 Posts
Latest Diesel Project

Here is my latest Diesel project a small Flitestreak , a top plane to fly
NX-687 is offline Find More Posts by NX-687
Reply With Quote
Old Jul 03, 2010, 04:02 PM
Registered User
Canada, ON, Hamilton
Joined Oct 2005
2,633 Posts
Stegla, the Parra is a nice engine. Clipclop seems to think so too. Have a look at their web site. I got one and will add a few pictures later. Or, as Gluehand suggests, you canít go wrong with the PAW .15.

Chas, thatís another good idea , but with my luck Iíd probably drill into the bolt. Patmcc, cutting the bolt seems like the best idea. Thereís little chance of slipping off the end of a drill bit or marking up the engine. Does anyone know what bolt thread and size this Merco is using?

NX-687, what engine do you have there? Perhaps clean it up a little and send in a few pictures. What does the U/C weigh?
JohnAV8R is offline Find More Posts by JohnAV8R
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Need help with two diesel engines ! cosmin Engines 4 Apr 18, 2014 07:18 PM
Diesel Engines Aeromister Engines 8 Sep 01, 2009 07:17 AM
WTB-Model Diesel Fuel slogo Aircraft - Fuel - Airplanes (FS/W) 3 Nov 13, 2004 09:42 PM
scale model of engines dw1122 Life, The Universe, and Politics 2 Apr 23, 2004 05:43 AM
diesel engines wyflyer_55 Fuel Plane Talk 7 Apr 22, 2002 02:45 AM