REFLECTOR:Keeping the ! out of Expensive Propellers

Scott Derrick reflector@tvbf.org
Mon, 02 Jun 2003 06:37:02 -0600


No experience with non-paved operations in a pusher, so just some ideas.

1.) Go for a shorter blade?  As I understand the vortex generated by a 
prop, a couple inches shorter reduces the problem a lot.

2.) Try an IVO prop if they make one for 300 HP.  Their blades are 
pretty tough.

3.) Always land and taxi with the speed brake down if he has one, I do.

Do all Chuck said except for that dead stick thing! ;-)

To minimize rock damage on take off I always try to take off from a 
rolling start.  I finish my runup(He's doing this in a very clean spot 
right?), I roll out on the runway and don't stop, just continue to 
slowly apply power, it takes a couple hundred feet before I'm at full 
power and rolling about 15-20 knots.

As far as sweeping the runway, I think sweeping the first 400 to 500 ft 
would eliminate most of the damage.

Scott



Chuck Jensen wrote:
> I assume the tarred aggregate is what we refer to as a "stabilized surface";
> kind of half way between a hard gravel road and asphalt.  Basically pea
> gravel with tar incorporated and rolled.  An excellent and inexpensive road
> for cars but allows a lot of aggregate to be dislodged which becomes coarse
> sandpaper for the prop.  Things to do?
> 
> 1.	See if they will put a seal coat on the runway and ramp after using
> a tractor boom to remove as much of the loose materials as possible.  Of
> course, if you are eating up MT props, pretty soon you could afford to seal
> coat it yourself.
> 
> 2.	If they won't seal coat it, at least see if they will run over it
> with a street sweeper to remove as much of the loose materials as possible.
> 
> 3.	During taxi use the absolute minimum of power; not easy with the
> differential braking.  During take off, apply the power very slowly
> (assuming you have lots of runway) to avoid creating a 200 hp vacuum cleaner
> which sucks up all the pebbles and rocks into the prop.
> 
> 4.	On landing, always turn the engine off 1-2 miles out and dead-stick
> it in.
> 
> I'm unaware of any real design things you can do.  You can minimize it by
> how you operate the engine/prop on the ground but that's about it.
> 
> Finally, if you prefer to continue replacing just props instead of the whole
> airplane, #4 can best be discounted.
> 
> Chuck
> 27GV
> 
> P.S. Since I don't have extensive legal fees budgeted for the current fiscal
> year, please ignore #4!!!!
> 
> 
> 
> 
> 
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Greg Poole
> Sent: Monday, June 02, 2003 4:41 AM
> To: reflector@tvbf.org
> Cc: Leon Howe
> Subject: REFLECTOR:Keeping the ! out of Expensive Propellers
> 
> 
> G'Day All,
> 
> .....Still waiting in the wings down here looking for clear evidence of
> success of established means for keeping rocks etc out of pusher propellers.
> Despite all precautions, have all but trashed two MT propellers for 40 hours
> use in the XL we built down here.  As previously indicated, when you
> amortise the cost of a prop. this makes landings very expensive!  (most
> strips down here are tarred aggregate rather than concrete).
> 
> The owner of the XL  - Leon Howe, has asked me to again ask for what any of
> you blokes have done to get around this - diagrams, pictures, descriptions -
> all accepted without complaint!
> 
> Kind regards,
> 
> Greg in Sydney.
> 
> 
> ----- Original Message ----- 
> From: "steve korney" <s_korney@hotmail.com>
> To: <reflector@tvbf.org>
> Sent: Thursday, May 29, 2003 5:02 AM
> Subject: Re: AW: REFLECTOR:Help me buy a house...on an airport
> 
> 
> 
>>Landing on a airport that is less then 3000 ft. long is not a good idea in
> 
> a
> 
>>Velocity...If you are an experienced pilot with lots of confidence then
> 
> OK,
> 
>>try it...But, I for one would caution anyone who tries to be very careful
>>about brakes, nose gear, main gear, debris on strip, density altitude,
> 
> strip
> 
>>condition, on and on...These aircraft are not designed for short field
> 
> take
> 
>>offs and landings...
>>
>>My $.02
>>
>>Your mileage WILL vary...
>>
>>
>>
>>Best... Steve
>>
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