Graham-
I have been talking with the Jab. people in Tenn. as I go throught it and I
purchased one of the little 30 degree elbows from them.=C2- Jab. also re
commends thoroughly smoothing the area around the 2 1/4 inch tube leading o
ut of the airbox and I have done so.=C2- This would all seem to support a
smooth flow, but at this point I know nothing, since it is not yet running
.=C2- As an initial shot, I am going 100% with the Jab. recommendations,
then we will see.=C2- Their feeling is that cooling will be OK.=C2- The
more recent engines (mine being one) have larger fins on 5 and 6, and they
say this helps.=C2- Also, on the tri-gear, there is an easier exit for c
ooling air, and that supposedly helps too.=C2- I have individual EGT prob
es on each cylinder, so will be able to watch it.=C2- Also, they say that
the baffles you can install in the cooling shrouds can be tuned to get it
just right.=C2- As I say, I have no way of knowing if any on this is corr
ect.=C2- Talk to me in about 3 months.
You can also install pipes off the cooling shroud pointed at components you
wish to cool, and I may find it necessary to do that with the fuel pump.
=C2-
Jim
----- Original Message -----
From: "Graham Singleton" <grahamsingleton@btinternet.com>
Sent: Friday, January 22, 2010 7:55:16 PM GMT -05:00 US/Canada Eastern
Subject: Re: Europa-List: Wondering
On 22/01/2010 22:11, jimpuglise@comcast.net wrote:
EGT and CHT are all you will need to be careful of.=C2- I am in the middl
e of installing a 3300 in mine; am going the Sensenitch prop as John has.
=C2- One of the secrets seems to be the amount of twist in the prop near
the hub, so that it throws a lot of air into the cooling ports.=C2- This
is why the Senesenitch is recommended.=C2- I don't know anything about th
e Whirlwind.=C2- Ther are several Jabs. flying in the US with excellent p
erformance.=C2- Many of the problems have been in monos or with VP props.
=C2-
Jim Puglise A-283.
Carburation affects cooling. The carb needs air going straight in evenly, a
smooth elbow into the carb doesn't work, different air velocity across the
inlet which causes different mixture in the front and rear cylinders, (I'm
thinking aloud here) could be that turbulent flow is needed. A plenum that
feds straight not curved seems to work better. A box with in and out tubes
@90deg works. Turbulence might help evaporate the fuel droplets spraying i
nto the inlet manifolds. Drops won't go round corners.
There's a guy in UK who worked this out, Anthony Higgins but I don't have h
is contact details, (@#%$^&windoze crash :-(=C2- Rally driver and Europa
builder. Are you there Tony?
Tony helped cure an overheating Jab 6, I spent hours on it and failed.
Which reminds me, I recommend you fit a fuel bleed back downstream of th en
gine driven pump. Pump is bolted to the engine and will get hot, fuel vapor
isation is a possibility. One accident due to this suspected, not yet prove
n. Fuel was Avgas.
Graham
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