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Benjamin Q
Joined: 04 Mar 2009
Posts: 13
Location: Twentynine Palms, CA
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 Posted: Thu May 07, 2009 6:27 pm Post subject: Prince P-tip propeller |
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I am going to put a Jabiru 2200 on my 701. I have been looking into using a Prince P-tip propeller. Supposedly the p-tip allows a blade of smaller diameter to be as effective as a larger propeller because the tips "delays the tip vorticies which cause drag and turbulence within the propeller arc." They also claim that "a 72" diameter propeller without a P-TIP will give a volume of air from the propeller of approximately 68" in diameter; a P-TIP propeller will provide 72" of air volume."
Additionally the propellers are said to include automatic pitch changing. "The propeller has a fixed pitch that relies on the forward pull of the propeller to automatically provide pitch change proportional to the amount of force being applied to the propeller disk."
I have looked for information on some of the forums and the few that have the propeller seem to think that they give modest increases in performance and efficiency.
The reason I am so interested in these propellers is because it seems like they might be something of a silver bullet for some of the weaknesses you find in the Jabiru. The Jabiru has to use a smaller prop because they spin up to 3300 rpms. You are limited to a 68" prop instead of the 72" prop you would usually find on a Rotax. Conveniently, 68" to 72" is the difference Prince claims for their props. Additionally the automatic pitch changing could help with the slightly weaker climb and takeoff performance of the Jabiru as compared to the Rotax. It's not that I think that the Jabiru will out perform the Rotax with the P-tip Prop, but I think it will get closer then if I put on the wood or ground adjustable composite sensenich that is packaged with Jabiru's Firewall Forward kit.
I called Jabiru USA and talked to someone there and they didn't recommend the Prince P-tip. Their reasons were cost and consistency. They said that they got a few P-tip propellers one time and when they were put on the same engine, there was a slight difference in the max rpms in each propeller. I think they said about a 20 rpm difference, but I might be remembering that wrong.
Anyway as far as cost, I'm not sure thats and issue either. The cost of the p-tip is actually less then the composite ground adjustable sensenich. I'm not entirely sure the consistency argument is that strong either. The propellers are individually made in order to be application specific, so you can expect there to be at least a slight difference in each propeller.
I also called Prince Aircraft Company and talked to Lonnie Prince, the owner of the company. He told me that if I got the propeller and it wasn't performing like I thought it should, he would take it back and tweak it at the factory for free. The research I have done on the company seems good. They have been around for a while and have a pretty diverse business. Lonnie was a super nice guy, but as an engineer, I really wish that he had some hard core dynamic flow analysis, or experimental data I could take a look at. Realistically, I don't think Zenith has done hardcore dynamic flow analysis either. More of a wish on my part, not a criticism.
I have heard that a few 601s have Prince P-tips with good results, but that's a little different in application. Has anyone tried a P-tip on a slower STOL Airplane? Has anyone else looked into this? Even with the non-recommendation from Jabiru, I am still leaning toward the P-tip. Professionally, I appreciate the way the design takes advantage of innovative engineering to turn out a unique solution. If anyone wants to take a look at the website its http://www.princeaircraft.com/TheProp.aspx
I would appreciate any comments you guys have. Even though I have only had my kit for a month, I am already done with my rudder, horizontal stabilizer, elevator, slats and flaperons. I have two weeks of leave coming up and I hope to be through the wings and into the fuselage. Its amazing how much you can get done in a 12 hour day. The propellers have a 13 week lead time, so if this is the direction I am going, I need to do it soon, otherwise I'll be have a finished airplane in my garage waiting for a propeller.
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challgren(at)mac.com
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| Posted: Fri May 08, 2009 7:43 am Post subject: Prince P-tip propeller |
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On May 7, 2009, at 20:28 , Benjamin Q wrote:
| Quote: |
>
I am going to put a Jabiru 2200 on my 701. I have been looking into
using a Prince P-tip propeller. Supposedly the p-tip allows a blade
of smaller diameter to be as effective as a larger propeller because
the tips "delays the tip vorticies which cause drag and turbulence
within the propeller arc." They also claim that "a 72" diameter
propeller without a P-TIP will give a volume of air from the
propeller of approximately 68" in diameter; a P-TIP propeller will
provide 72" of air volume."
Additionally the propellers are said to include automatic pitch
changing. "The propeller has a fixed pitch that relies on the
forward pull of the propeller to automatically provide pitch change
proportional to the amount of force being applied to the propeller
disk."
I have looked for information on some of the forums and the few
that have the propeller seem to think that they give modest
increases in performance and efficiency.
The reason I am so interested in these propellers is because it
seems like they might be something of a silver bullet for some of
the weaknesses you find in the Jabiru. The Jabiru has to use a
smaller prop because they spin up to 3300 rpms. You are limited to
a 68" prop instead of the 72" prop you would usually find on a
Rotax. Conveniently, 68" to 72" is the difference Prince claims for
their props. Additionally the automatic pitch changing could help
with the slightly weaker climb and takeoff performance of the Jabiru
as compared to the Rotax. It's not that I think that the Jabiru
will out perform the Rotax with the P-tip Prop, but I think it will
get closer then if I put on the wood or ground adjustable composite
sensenich that is packaged with Jabiru's Firewall Forward kit.
I called Jabiru USA and talked to someone there and they didn't
recommend the Prince P-tip. Their reasons were cost and
consistency. They said that they got a few P-tip propellers one
time and when they were put on the same engine, there was a slight
difference in the max rpms in each propeller. I think they said
about a 20 rpm difference, but I might be remembering that wrong.
Anyway as far as cost, I'm not sure thats and issue either. The
cost of the p-tip is actually less then the composite ground
adjustable sensenich. I'm not entirely sure the consistency
argument is that strong either. The propellers are individually
made in order to be application specific, so you can expect there to
be at least a slight difference in each propeller.
I also called Prince Aircraft Company and talked to Lonnie Prince,
the owner of the company. He told me that if I got the propeller
and it wasn't performing like I thought it should, he would take it
back and tweak it at the factory for free. The research I have done
on the company seems good. They have been around for a while and
have a pretty diverse business. Lonnie was a super nice guy, but as
an engineer, I really wish that he had some hard core dynamic flow
analysis, or experimental data I could take a look at.
Realistically, I don't think Zenith has done hardcore dynamic flow
analysis either. More of a wish on my part, not a criticism.
I have heard that a few 601s have Prince P-tips with good results,
but that's a little different in application. Has anyone tried a P-
tip on a slower STOL Airplane? Has anyone else looked into this?
Even with the non-recommendation from Jabiru, I am still leaning
toward the P-tip. Professionally, I appreciate the way the design
takes advantage of innovative engineering to turn out a unique
solution. If anyone wants to take a look at the website its http://www.princeaircraft.com/TheProp.aspx
I would appreciate any comments you guys have. Even though I have
only had my kit for a month, I am already done with my rudder,
horizontal stabilizer, elevator, slats and flaperons. I have two
weeks of leave coming up and I hope to be through the wings and into
the fuselage. Its amazing how much you can get done in a 12 hour
day. The propellers have a 13 week lead time, so if this is the
direction I am going, I need to do it soon, otherwise I'll be have a
finished airplane in my garage waiting for a propeller.
Benjamin:
|
I had a Prince 58" by 48 degree prop on my 601 HDS and I did get very
slightly better performance from it than from a Sensenich 64 X 49.
After the Sensenich was damaged due to a faulty spinner I got a GT
which underperformed the previous two by a small amount. The slightly
improved performance of the Prince was not worth the increased cost.
It was, however, the hands-down winner of the beauty contest. I still
have the Prince and plan to use it on my first taxi tests around my
pasture here at 8,000 ' msl.
As I remember I got about 2900 rpm on the takeoff roll with the Prince
at 5500', the elevation at Front Range, which is very close to DIA.
With the Sensenich the takeoff rpm was closer to 2750 which may
account for its slightly underperforming the Prince. The near sea
level performance of the Prince at Oshkosh was awesome.
I believe Jim Sagerser could give you more information on the Prince
performance on the 701. He was up yesterday assisting me and he has
had some experience with different props on his 701 with a 3300. I
believe Jim's email address is >lvuman(at)gmail.com<
Stan
701/3300
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cffd(at)pgrb.com
Guest
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| Posted: Sun May 10, 2009 7:23 am Post subject: Prince P-tip propeller |
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Benjamin,
I have a 701 with a Jab 2200 and a Prince P-Tip prop. 64x26. Greater than
64 inches may give you tip drag as the tip speed approaches mach 0.9 at 3300
rpm. I think my prop is a bit under pitched. Recently I researched what
others are using on similar airplanes and a Jab 2200. I tried a Tenn prop
64x34. As expected, my takeoff roll increased, but the climb rate was cut
in half and only gained 2 or 3 mph in cruise. FOr now the Prince is going
back on.
Chuck D.
N701TX
| Quote: | Subject: Prince P-tip propeller
From: "Benjamin Q" <ben.queener(at)gmail.com>
I am going to put a Jabiru 2200 on my 701. I have been looking into using
a Prince
P-tip propeller. Supposedly the p-tip allows a blade of smaller diameter
to be as effective as a larger propeller because the tips "delays the tip
vorticies
which cause drag and turbulence within the propeller arc." They also
claim
that "a 72" diameter propeller without a P-TIP will give a volume of air
from the propeller of approximately 68" in diameter; a P-TIP propeller
will provide
72" of air volume."
Additionally the propellers are said to include automatic pitch
changing.
"The propeller has a fixed pitch that relies on the forward pull of the
propeller
to automatically provide pitch change proportional to the amount of force
being applied to the propeller disk."
I have looked for information on some of the forums and the few that
have the
propeller seem to think that they give modest increases in performance and
efficiency.
|
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Dwight Early
Joined: 15 Jul 2008
Posts: 17
Location: Indiana
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| Posted: Thu May 14, 2009 2:35 am Post subject: Re: Prince P-tip propeller |
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Benjamin, I also run the Prince P Tip 60x33 on a Revmaster 75 hp direct drive 701. It is not working on my application I think it has to much pitch, I am not achieving the static rpms needed for a full power takeoff. With all that being said, why not try the ground adjustable Sensenich that Jabiru sells with their firewall forward for the 701. I know it is a little pricey but if you have to buy 2 or more props to hit the sweet spot that is needed for your application then it might be worth it. I have a friend that flys that combination and is very happy with it.
Just my 2 cents worth. Good luck!
Do Not Archive
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_________________
Dwight Early
N701EF
Zenith CH701/Revmaster
Daleville, In |
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Benjamin Q
Joined: 04 Mar 2009
Posts: 13
Location: Twentynine Palms, CA
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| Posted: Fri May 15, 2009 9:59 am Post subject: Re: Prince P-tip propeller |
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Thank you everyone for your comments and advice. I have been able to track down a few people who have p-tips and the general consensus is that the p-tip will at least meet, and probably moderately exceed the performance of the sensenich. A couple of these people had both propellers, so they were able to better do a cross evaluation. I also was told that on the Zenith with a Jabiru, the p-tip lowered the cylinder head temperatures. As I stated before, the cost isn't really that different, and less then the composite ground adjustable sensenich. After considering all these factors, I went ahead and ordered a p-tip.
I explained that I was more interested in climb and takeoff then cruise, so the pitch was reduced from 29" to 28". Once I finish (around September) I will do extensive testing and make sure to post the numbers for everybody.
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