Dieselising a Bee - Be warned!

You need the "car" crank in order for them to hold up to the higher compression ratio. Davis Diesel sells kits where you get both a diesel head and a suitable crank.

The problem with the standard crank is that they are hardened too much, effectively making them brittle.

Our diesel cranks are "Killer Bee" style but, for the hardening, we deviated from OEM specs and made them softer.

A diesel crank and diesel head conversion kit we retail for $27.90 in total.

http://coxengines.ca/cox-.049-killer-bee-diesel-crank.html

http://coxengines.ca/diesel-head-conversion-for-cox-049.html

and $2 more for the red version:

http://coxengines.ca/diesel-head-conversion-for-cox-049-red.html

what type of fuel do you use for a set up like that??regular diesel from a pump,or some kind of special blend,i think i might like to mess with that if the fuel isnt hard to get..

Special fuel. Here are links to some fuel guides:

http://coxengines.ca/files/FG.pdf

http://coxengines.ca/files/DFD.pdf

Diesel fuel for model engines can be the subject of great debate.

For engines over 1cc, I have always followed Progress Aero Works recommendations:-

Castor Oil, Paraffin, Ether, Iso Propyl Nitrate or similar


Running in ----------------- 30%, 35%, 33%, 2%
Fully run in ----------------- 25%, 40%, 33%, 2%
Fully run in
- BR Models ---------------- 20%, 48%, 30%, 2%
Fully run in
- TBR only
(Racing and Speed) -------- 15%, 50%, 32-33%, 2-3%

0.5 - 1cc I would increase ether to 35%

sub 0.5cc I would start at 40% ether

Just a note: Paraffin(UK English) = Kerosene(Yankee Speak)

I am awash with "diesel stuff" and was just trying to warn anyone who converted what would (not might!) happen if attention wasn't paid to changing the crankshaft in a bee. It was another experiment of mine.



I wouldn't dare fire up the Pee Wee. Will probably transfer the head to a Tee Dee.



I still have lots to play with (apart from my own constructions!)

The PeeWee runs fine as a diesel. Just use a large enough prop (6x3) to keep the revs and compression down;

That is good to know. I would not have risked it without knowing.

Hi Ian!

Happy new year!!

well, i been playing with my two cox conversions... i been reading a lot, and mostly all comments are: cox are not suitable for diesel.... the crank is to fragile....

i get 2 diesel heads from hobbyking as Cox International is not shipping to Mexico. and i ordered just one diesel crank. so i decided to make my tries with bought.

after 12-20 runs with stock crank, my engine still going. even the teflon disk is in good working order. I even start my babyDieselBee at same time as my MP jet.... they work very similar, the cox needs maybe 6 more flips to start that my MP, but they can run as low revs... what is i´m looking for..... love FF models (sport) and regular cox, even with 10 nitro and bigger prop can be to powerful for some models...

about dieselized pee wee..... well, my head DDD is well made, but maybe bad calculated, as even at lower compression settings is to hi, and i broke a crank..... so i sanded a little the contrapiston and will give a try soon.

Here a couple videos of my cox
https://www.youtube.com/watch?v=ceIPdA9-JNo

https://www.youtube.com/watch?v=s9mgwBEuVqo


https://www.youtube.com/watch?v=F0tjD4CwcA0

https://www.youtube.com/watch?v=0yAX1zGN9B0

I messed round with making myself some diesel cox heads in the late 80s, the 049s seemed ok i never broke a crank on the 049s.... but... the peewee...the crankweb scapped as i was flicking it on the first little pop from the engine, I fitted a new crankshaft....( had spares then ) and the new crank snapped first flick again so I changed again....and made a bit of wood to add a dome shape to the aluminium drink can i was using as a compresion disk, tried again and it runs fine now still on diesel
For fuel originaly i used commercial fuels but often now I just use equal parts by volue of diethyl ether ,car pump diesel and castor oil, sometimes with a few ml of mekp ( fiberglass peroxide catylist) added per litre of fuel but usualy just the 3 main components

MiniatureAircraftFactory wrote:I messed round with making myself some diesel cox heads in the late 80s, the 049s seemed ok i never broke a crank on the 049s.... but... the peewee...the crankweb scapped as i was flicking it on the first little pop from the engine, I fitted a new crankshaft....( had spares then ) and the new crank snapped first flick again so I changed again....and made a bit of wood to add a dome shape to the aluminium drink can i was using as a compresion disk, tried again and it runs fine now still on diesel
For fuel originaly i used commercial fuels but often now I just use equal parts by volue of diethyl ether ,car pump diesel and castor oil, sometimes with a few ml of mekp ( fiberglass peroxide catylist) added per litre of fuel but usualy just the 3 main components

I'm surprised that the car pump diesel works ok. Normally you need to use kerosene/paraffin.

Car diesel is better in some ways as it contains the anti knock additives, My original fuel i mixed used runny bbq lighting fluid, red diesef for heating also works fine