Today's Message Index:
----------------------
1. 08:00 AM - Damaged Prop? (LessDragProd@aol.com)
2. 08:33 AM - Lycoming - tractor engine or turbine smooth? (LessDragProd@aol.com)
3. 08:37 AM - Re: Damaged Prop? (AI Nut)
4. 08:41 AM - Re: Lycoming - tractor engine or turbine smooth? (AI Nut)
Message 1
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--> RV10-List message posted by: LessDragProd@aol.com
What do you do if you damage a prop?
Ask for help.
I was flying back from Van's Fly-In a couple years ago with another RV-3.
When we landed at the first stop, the other RV-3 made a bad landing (bouncy)
and clipped the tips of his propeller on the runway. Unfortunately, it also
split out a piece on one blade from the tip to the root near the trailing
edge. Prop scrapped.
The RV-3 owner contacted the local EAA group. There was an RV-4 on the
field that was for sale and not being flown. They loaned the RV-3 owner the RV-4
propeller to fly home.
A Velocity with an MT Propeller was landing at Sun-N-Fun last year, and had
to make a go-around right as they were flaring to land. In applying full
power with the wheels on the runway, the Velocity over-rotated and the propeller
contacted the runway. This removed a small amount of material from each of
the blade tips.
Although the MT Propeller manual provides specific criteria for damage
repair, the owner came to the MT Propeller booth to ask for help.
An MT Propeller factory representative looked at the damage, and determined
that there were no spanwise cracks in the blades.
The repair was to trim the blades to the same length. The permanent repair
would be to trim the blades to the same length and paint the exposed wood.
Having the propeller rebalanced at the earliest opportunity was also
recommended.
Regards,
Jim Ayers
Message 2
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| Subject: | Lycoming - tractor engine or turbine smooth? |
--> RV10-List message posted by: LessDragProd@aol.com
Lycoming - tractor engine or turbine smooth?
This is the real question that needs to be asked when you are considering
which propeller to buy.
I had an opportunity to test four different constant speed propellers on one
aircraft. There were three different 2 blade propellers and one 3 blade
propeller. This aircraft was owned by a friend who flew the aircraft. I just
went along as the observer and data recorder.
The original CS propeller on the aircraft had been dynamically balanced on
the engine. Since the plan was to leave the original propeller on the
aircraft when we were finished with the testing, we did not removed the dynamic
balance weights from the engine ring gear.
All three of the 2 blade propellers had about the same vibration level
during their flights.
Then we flew the 3 blade propeller. On the takeoff roll and initial climb,
I noticed the pilot was highly stressed about something. About mid field, as
we were climbing out, he finally said that something must be wrong with the
engine. That the engine wasn't producing power.
We laughed about this later.
We seem to expect a certain vibration level which can be directly related to
the engine power. We don't even think about this. And it's not something
that any instructor I have had has ever talked about. It's just there.
I've been told that a 2 blade propeller has a 2nd order harmonic on the
Lycoming engine.
And the 3 blade propeller does not have the 2nd order harmonic on the
Lycoming engine.
What does this really mean?
On another test sequence, I had an opportunity to again ride in a friends
aircraft. On this friends Harmon Rocket 2 with a stock Lycoming IO-540-C4B5,
we removed a 2 blade propeller and installed a 3 blade propeller.
The 3 blade propeller made the Lycoming run like it was an electric motor,
it was so vibration free.
When we install a second 2 blade propeller, the same old vibration came
right back. At the same level as the first 2 blade propeller.
So the question goes back to you, the builder/flyers. Do you want "turbine
smooth" or "tractor engine"?
Regards,
Jim Ayers
Message 3
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| Subject: | Re: Damaged Prop? |
--> RV10-List message posted by: AI Nut <ainut@hiwaay.net>
It is almost mandatory to get the crank checked whenever one has a prop
strike. A friend of mine did this when doing an emergency landing in a
field. Prop, spinner, and hub all looked good visually, but he had the
crank checked anyway. Good thing, too, as it had cracks necessitating
replacement.
David
LessDragProd@aol.com wrote:
>--> RV10-List message posted by: LessDragProd@aol.com
>
>What do you do if you damage a prop?
>
>Ask for help.
>
>I was flying back from Van's Fly-In a couple years ago with another RV-3.
>When we landed at the first stop, the other RV-3 made a bad landing (bouncy)
>and clipped the tips of his propeller on the runway. Unfortunately, it also
>split out a piece on one blade from the tip to the root near the trailing
>edge. Prop scrapped.
>The RV-3 owner contacted the local EAA group. There was an RV-4 on the
>field that was for sale and not being flown. They loaned the RV-3 owner the
RV-4
>propeller to fly home.
>
>A Velocity with an MT Propeller was landing at Sun-N-Fun last year, and had
>to make a go-around right as they were flaring to land. In applying full
>power with the wheels on the runway, the Velocity over-rotated and the propeller
>contacted the runway. This removed a small amount of material from each of
>the blade tips.
>Although the MT Propeller manual provides specific criteria for damage
>repair, the owner came to the MT Propeller booth to ask for help.
>An MT Propeller factory representative looked at the damage, and determined
>that there were no spanwise cracks in the blades.
>The repair was to trim the blades to the same length. The permanent repair
>would be to trim the blades to the same length and paint the exposed wood.
>Having the propeller rebalanced at the earliest opportunity was also
>recommended.
>
>Regards,
>Jim Ayers
>
>
>.
>
>
>
Message 4
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| Subject: | Re: Lycoming - tractor engine or turbine smooth? |
--> RV10-List message posted by: AI Nut <ainut@hiwaay.net>
It may be smoother, but I'm told by prop manufacturers that one will
lose a few kts in cruise with a 3-blade. I opted for smoother.
David
LessDragProd@aol.com wrote:
>--> RV10-List message posted by: LessDragProd@aol.com
>
>Lycoming - tractor engine or turbine smooth?
>
>This is the real question that needs to be asked when you are considering
>which propeller to buy.
>
>I had an opportunity to test four different constant speed propellers on one
>aircraft. There were three different 2 blade propellers and one 3 blade
>propeller. This aircraft was owned by a friend who flew the aircraft. I just
>went along as the observer and data recorder.
>
>The original CS propeller on the aircraft had been dynamically balanced on
>the engine. Since the plan was to leave the original propeller on the
>aircraft when we were finished with the testing, we did not removed the dynamic
>balance weights from the engine ring gear.
>
>All three of the 2 blade propellers had about the same vibration level
>during their flights.
>
>Then we flew the 3 blade propeller. On the takeoff roll and initial climb,
>I noticed the pilot was highly stressed about something. About mid field, as
>we were climbing out, he finally said that something must be wrong with the
>engine. That the engine wasn't producing power.
>
>We laughed about this later.
>
>We seem to expect a certain vibration level which can be directly related to
>the engine power. We don't even think about this. And it's not something
>that any instructor I have had has ever talked about. It's just there.
>
>I've been told that a 2 blade propeller has a 2nd order harmonic on the
>Lycoming engine.
>
>And the 3 blade propeller does not have the 2nd order harmonic on the
>Lycoming engine.
>
>What does this really mean?
>
>On another test sequence, I had an opportunity to again ride in a friends
>aircraft. On this friends Harmon Rocket 2 with a stock Lycoming IO-540-C4B5,
>we removed a 2 blade propeller and installed a 3 blade propeller.
>The 3 blade propeller made the Lycoming run like it was an electric motor,
>it was so vibration free.
>When we install a second 2 blade propeller, the same old vibration came
>right back. At the same level as the first 2 blade propeller.
>
>So the question goes back to you, the builder/flyers. Do you want "turbine
>smooth" or "tractor engine"?
>
>Regards,
>Jim Ayers
>
>
>.
>
>
>
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