Jab Engines - the good and the bad?

[KFA]

Stefan, hoe ver is daai vliegtuig van my? My gat juik en kannie meer wag nie?

Die kit se weldments sal oor so 3 weke reg wees maar ek gaan Holland en Duitsland toe vanaf die 12de April tot die 27ste so ek kan ongelukkig eers as ek terug kom die laaste goed van die kit bymekaar kry. So die delivery datum bly ongeveer 1ste week in Mei

[Jean Crous]

Stefan, hoe ver is daai vliegtuig van my? My gat juik en kannie meer wag nie?

Die kit se weldments sal oor so 3 weke reg wees maar ek gaan Holland en Duitsland toe vanaf die 12de April tot die 27ste so ek kan ongelukkig eers as ek terug kom die laaste goed van die kit bymekaar kry. So die delivery datum bly ongeveer 1ste week in Mei

Hy gaan leer Duits praat so tussen die bier drinkery deur Dan gaat al jou se pampiere in Duits wees
Lekker kuier Stefan
Jean

[HansK]

In the words of the well known and highly respected Kevin Hopper "fuel it, cool it and lube it, and it will run forever" - havent heard a bad word about a jabi' engine, know first had of 2 engine outs both fuel related, one resulted in a LOB and the other, simply restarted and carried on flying... (cautiously of course)...

I agree, but a Jabbie must be fed with Avgas.!!! I also strongly suggest to do the carb mod on the engine, that is for better fuel atomization.

[McCraken]

I agree with HansK. Bought an aircraft with 96hrs TT on the Jabi 2200. Have just spent a lot of money, partly because it was run on Mogas.

[KFA]

850 hr's of training on MOGAS 95 unleaded and no problems BUT we spent a hell of a lot of time to get the EGT's running equal as well as getting the CHT's very low. We are running at 670-700 EGT and 125-135 degr C CHT

[Nick]

There has been a spate of engine failures on Jab trainers at Rhino Park near Pretoria - attributed to high CHT and EGTs, causing failed valves. This was not one or 2, but rather a cluster of Jabs coming out of the sky in a short period as a result of the fan stopping, all in a couple of months, during the cold Winter. I understand that it was this cluster of failures which triggered the Jab SA Avgas only directive of a few months back, abrogating the Mogas or Avgas compliance detailed in more recently manufactured Jab POHs and in much of the company publicity.

Cold, dense, oxygen-rich air, all other things being equal, is associated with leaner mixtures. Leaner mixtures, in turn, are associated with high CHTs. Mogas, all other things being equal, runs hotter than Avgas.

I have most of my megre 117 hours on Jabs (a bit on Cessnas and Rotax powered Tecnams) - I love the Jab airframes - but as things presently stand, from what I know of CHT problems from the flight school I trained at and the number of Jab powered aircraft where the engines have significantly shorter time than the airframes, from problems in the UK and Australia reported with Jab power plants, from personal conversations with at least 4 AMOs who service Jabs; I wouldn't buy a Jab powered aircraft, I'd stick to Rotax - 'orrible high-revving snowmobile noise and all! This may change with the development of the new Jab fuel injection system.

That said, some guys seem to have this Jab CHT issue under control, even using mogas - by working on carb jets, avoiding excessively lean mixtures - again lean mix is associated with high CHTs - some even run different carb jets for winter and summer. It would no doubt be prudent to have accurate CHT and ECG probes on each cylinder, not just one as a sample. It seems you have to become something of a fundi to have the best chance of avoiding trouble with the Jab motors, of making anything approaching TBO.

[Dish]

Im not sure I agree with HansK's comment that a jabbi engine must be run on avgas... I have 400 Hours on mine and it has never missed a beat. I called Andrew Pappas (when I took delivery of mine 200 hrs ago - second hand of course) and asked advice from him. He said 95 octane is perfect.. - The Operators manual specifies Mogas 95 Minimum or Avgas... Occasionally I top up the fuel tank with Avgas if it is available but havent (touch wood) had any problems. I Know that this debate has been going for ages and im happy to admit if im wrong... but can we not get a definitive answer from the manufacturer. I know Sue Sing had problems once on a plane that she had bought where the previous owner had run 93... I am a bantam fan but moreso a Jabi engine fan.... Its reliable, cost effective to run, and suits my needs perfectly...