Airboat Lycoming's

[Lou]

Can anyone tell me the difference between the motors on airboats and
the motors in airplanes?
I notice quite a few airboat engines at 1/4 of the price of airplane
engines. I figure if your going to tear down and rebuild anyway, why
spend the extra cash? So far the only difference I can tell is the
certification which brings the cost up.
Lou

[Orval Fairbairn]

In article . com>,
"Lou" > wrote:

> Can anyone tell me the difference between the motors on airboats and
> the motors in airplanes?
> I notice quite a few airboat engines at 1/4 of the price of airplane
> engines. I figure if your going to tear down and rebuild anyway, why
> spend the extra cash? So far the only difference I can tell is the
> certification which brings the cost up.
> Lou

They are very often recovered from wrecked aircraft and MAY have
significant parts (cranks, cams, cylinders, etc.) that are out of
airworthy tolerances.

It is a case of caveat emptor.

--
Remve "_" from email to reply to me personally.

[john smith]

> > Can anyone tell me the difference between the motors on airboats and
> > the motors in airplanes?
> > I notice quite a few airboat engines at 1/4 of the price of airplane
> > engines. I figure if your going to tear down and rebuild anyway, why
> > spend the extra cash? So far the only difference I can tell is the
> > certification which brings the cost up.

The big question is, do they still have the dataplate?

[Orval Fairbairn]

In article >,
john smith > wrote:

> > > Can anyone tell me the difference between the motors on airboats and
> > > the motors in airplanes?
> > > I notice quite a few airboat engines at 1/4 of the price of airplane
> > > engines. I figure if your going to tear down and rebuild anyway, why
> > > spend the extra cash? So far the only difference I can tell is the
> > > certification which brings the cost up.
>
> The big question is, do they still have the dataplate?

They may -- or they may not -- there is no requirement for a dataplate
on an airboat engine!

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[Ben Hallert]

>They may -- or they may not -- there is no requirement for a dataplate
>on an airboat engine!
I'm guessing that John Smith is asking because the dataplate might be
the difference between being able to have it remanned and be certified
vs. just being another non-certified engine. Kinda like home
'remodels' where they knock down everything but one interior wall, then
build a whole new house around it. By keeping that one well documented
wall original, the builder avoids the tax consequences of construction
a whole new building vs. just 'fixing up' the existing.

[Orval Fairbairn]

In article . com>,
"Ben Hallert" > wrote:

> >They may -- or they may not -- there is no requirement for a dataplate
> >on an airboat engine!
> I'm guessing that John Smith is asking because the dataplate might be
> the difference between being able to have it remanned and be certified
> vs. just being another non-certified engine. Kinda like home
> 'remodels' where they knock down everything but one interior wall, then
> build a whole new house around it. By keeping that one well documented
> wall original, the builder avoids the tax consequences of construction
> a whole new building vs. just 'fixing up' the existing.

I forgot to mention that some Lycomings have the S/N stamped on the
crankcase, in addition to the data plate.

--
Remve "_" from email to reply to me personally.

[Lou]

I guess what I'm curious about is, if your going to tear down and
rebuild the entire engine, why not buy one of these airboat motors?

[Ben Hallert]

Hi Lou,

I'll rephrase what I think John Smith was suggesting another way:
Buying an airboat Lycoming for your airplane is probably fine, and if
it has the dataplate, it might even be a good investment because you'll
be able to use it in certified engines so it'll have higher resale
value.

John, if I'm putting words in your mouth, let me know.

Regards,

Ben Hallert

[Lou]

Ben Hallert wrote:
> Hi Lou,
>
> I'll rephrase what I think John Smith was suggesting another way:
> Buying an airboat Lycoming for your airplane is probably fine, and if
> it has the dataplate, it might even be a good investment because you'll
> be able to use it in certified engines so it'll have higher resale
> value.
>
> John, if I'm putting words in your mouth, let me know.
>
> Regards,
>
> Ben Hallert

Thanks, I see quite a bit of airboat motors for sale at 1/4 of the
price of aircraft. I plan on rebuilding anyway, so I figure why not?

Lou

[Capt.Doug]

>"Lou" wrote in message > Thanks, I see quite a bit of airboat motors for
sale at 1/4 of the
> price of aircraft. I plan on rebuilding anyway, so I figure why not?

Keep in mind that airboaters are not restricted to approved means of
repairing things. For example, airboaters can fill a cylinder head crack
with silver solder. That works for a while and then they radio for a tow
back to the docks. Would you have the same option of getting a tow if you
were flying behind that crack? Airboaters can install and operate propellers
that have problematic harmonic vibrations. The accumulated fatigue cycles on
the crankshaft may not lead to failure until you are flying behind that
crack. An airboater can limp home on 3 cylinders. Can you? It may be a good
bargain, but do yourself a favor and do a teardown.

D.

[Lou]

Capt.Doug wrote:
> >"Lou" wrote in message > Thanks, I see quite a bit of airboat motors for
> sale at 1/4 of the
> > price of aircraft. I plan on rebuilding anyway, so I figure why not?
>
> Keep in mind that airboaters are not restricted to approved means of
> repairing things. For example, airboaters can fill a cylinder head crack
> with silver solder. That works for a while and then they radio for a tow
> back to the docks. Would you have the same option of getting a tow if you
> were flying behind that crack? Airboaters can install and operate propellers
> that have problematic harmonic vibrations. The accumulated fatigue cycles on
> the crankshaft may not lead to failure until you are flying behind that
> crack. An airboater can limp home on 3 cylinders. Can you? It may be a good
> bargain, but do yourself a favor and do a teardown.
>
> D.



I agree Doug, I plan on doing a total tear down anyway. Better safe
than sorry.
Now, whats the difference between the airboat motor and a GPU?

Lou

[Capt. Geoffrey Thorpe]

"Lou" > wrote in message
ups.com...
>
>> >"Lou" wrote in message > Thanks, I see quite a bit of airboat motors
>> >for
>> sale at 1/4 of the
>> > price of aircraft. I plan on rebuilding anyway, so I figure why not?
>
>
> I agree Doug, I plan on doing a total tear down anyway. Better safe
> than sorry.
> Now, whats the difference between the airboat motor and a GPU?
>
> Lou
>

Two things.

One. You can actually find air boat motors to buy.

Two. A lot of air boat motors came out of airplanes so they were designed
with a propeller flange and the right kind of front bearing, aircraft style
motor mounts, etc. etc. etc. (Unlike the typical GPU).

If the crank was ground at an auto machine shop they may or may not have
preserved the fillets at each end of the bearing surface. If they ground a
square corner, you will want to replace the crank (assuming the original had
the fillet....). Better shops know not to do this, but you don't know until
you look - eh?

--
Capt. Geoffrey Thorpe
The Sea Hawk At WowWay D0t Com

[john smith]

> John, if I'm putting words in your mouth, let me know.

No, you and others have covered the topic well. I was unintentionally
brief and you stepped in and filled in the gap. Thank you.

[Bret Ludwig]

john smith wrote:
> > John, if I'm putting words in your mouth, let me know.
>
> No, you and others have covered the topic well. I was unintentionally
> brief and you stepped in and filled in the gap. Thank you.

One, as alluded to here, most airboat engines are built totally or
largely from scrounged UNAIRWORTHY parts. Many if not most will fail
under power sooner or later. Airboat use puts a lot of stresses on
these engines not originally figured on and not apparent in most
aviation uses.

Two, what parts in them not unairworthy are likely as not stolen.

Airboaters are slowly abandoning LyCon power. perhaps homebuilders
should more frequently take the hint.

[Flyingmonk]

Here's one for sale on Ebay right now
http://makeashorterlink.com/?C32052C4C