: Matt Barrow wrote:
: : Why in hell did you go for a Tanis heater instead of Reiff?
:
: - Get heat *AT* the head... not at the other end of the jug where it has
: to go
: by cooling fins designed to remove it to get where it's needed.

: That's not only a myth, but flat out wrong.

: http://www.reiffpreheat.com/FAQ.htm#QA11

I can see I stirred up a hornet's nest here. I don't care all that much
either way... I looked into it awhile back and decided that with appropriate
workarounds, Tannis provides better performance where it matters. In response to your
previous messages:

- Tannis does have workarounds for the CHT probe. I think they've got a combo
thermocouple and heater element, but I just use the spark-plug probes. They've also
got the extra-kludgy valve cover gasket heater... ick!

- Cost... yeah, that makes a difference. I got mine used.

- My statement regarding heat AT the head was poorly worded, but my point still
stands. I was not talking about interfering with cylinder cooling
(http://www.reiffpreheat.com/FAQ.htm#QA11)... rather the argument that heat flows well
the other way. If you read their rebuttal (http://www.reiffpreheat.com/FAQ.htm#QA10)
carefully, you see:

"Our testing of our system and the other brand showed that the cylinder temperature
measured at the top end of the cylinder mid-way between their element and ours was the
same with both systems. Not surprising since both are 50 watt heaters. They did a
test too, but they skewed the results in their favor by measuring the temp about 1
inch away from their heating element."

No surprise there... if you look at the cylinder, a point midway between the
CHT probe and the base of the cylinder barrel has almost the same amount of barrel
travel. Heat *will* flow in all directions from the source, but if you heat in the
center of the head, it'll get more heat *IN* the head than if you heat from the bottom
of the jug. The head is where the choke is, where the highest thermal load is once it
starts (read: uneven expansion initially).

Don't get me wrong... both products have issues, and they both are flinging
crap at the other to try to say that theirs is better. Aside from the expense and
complication of heating *all* cylinders (including ones with CHT probes), the Tannis
is a better engineered solution.... put heat where it's necessary. If you could seal
off and insulate the cowling extremely well so little heat is lost, everything inside
would eventually get toasty. In a finite time with imperfect insulation, I'd rather
put the heat where it's necessary.

Flame on...
-Cory



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************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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