Prop Pitch

[roger lee]

Your reaching and where in those quotes does it say "Vans is wrong".

Originally Posted by roger lee View Post
You need to forget about static. It should only be used to get in the ball park to do a flight test for the first flight.

Quote:
Originally Posted by roger lee View Post
Owners at sea level that never fly over 2K ft. should have a different prop pitch than people that fly out of Mammoth, CA or Leadville, CO.

Exactly!
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Both statements are absolutely true and any good prop MFG and Rotax will tell you the same thing.
This is what we teach in school. Fundamentals and concepts are important to understanding and education.

The thing is neither says Vans is wrong.

See you do agree on concept which isn't specific to Vans.

Your quote:
"So, they are using the same RPM value, but it will result in a totally different prop pitch. Higher density altitude also reduces thrust from the prop slightly, which influences the overall result, but in the end, each person will have a different prop pitch that (for most people) they will be entirely happy with.

p.s.
Leadville, CO is the highest airport in North America.

So you did get the general concept that I was stating all along and it didn't just apply only to Vans aircraft.

your quote:
"This works with the RV-12, with a specific engine and propeller mounted to the front."

True taken only when applied to Vans, but not true if we consider all 912 engine and prop applications and then the fundamentals and concepts are the same. It works for many different 912 aircraft (tractor and pusher) and with different MFG props and we'll leave the 912ULS as the engine which will cover EAB, ELSA and SLSA. I have run and tested as many or more Sensenich props than Vans has not to mention about a half dozen other prop MFG's. You work on one MFG plane and I work on all of them and a service center for several.

You can't win this one and I'll say this right up front.
VANS DOES IT RIGHT and the theory and concept isn't specific to Vans and is applicable to all. Understanding the fundamentals makes a better informed owner a happier end user with his RV12 that can then exercise his own decision making.

[rgmwa]

Hey guys. As one of the RV-12 audience interested in getting a broad education, I appreciate the input and advice that both of you provide. When it comes to my aircraft, I'll follow Vans advice since they know it best, but maybe do so with greater understanding based on what both of you say. How about we call it a draw on this one and move on?

[RFSchaller]

Good example of how experts can disagree. I have rarely skinned a cat twice the same way.

[roger lee]

Nothing personal with me.
I love to swap ideas, training methods, shortcuts and especially new information just out hot off the press from MFG's like Rotax and of course cat skinning. It is just like debate class was back in school. It would be a dull world if we all thought alike and then nothing would ever get done. If you can't be opened minded and learn why live.

I have heard from several friends with RV's that Scott and I are entertaining and we don't even get paid for it.

p.s
Just an FYI
I just had an RV12 owner call this afternoon from northern AZ. with overheating problems. He was using Evans coolant. It is not recommended by Rotax any longer and carries a 20F-30F temp penalty. Better to stay with the now more conventional recommended 50/50 mix with more heat absorbing properties.

[RFSchaller]

I always preferred the water mix. My reasoning was it offered more flexibility on cross countries if I ever had to add coolant. So far (175hrs) I have never had to add any.

[roger lee]

The 50/50 water mix is easier to deal with for sure. A little extra 50/50 if needed or just some distilled water in the reservoir. I usually only see mild oozing from a screwed in joint on a water connection if the reservoir leaks down a tad. It is usually very slow and easy to fix.



Rotax 912is engine:
There are about 35-40 engines in the US right now and 100 is projected by year's end. The only issue right now is mechanics for this engine are limited. Maybe 10 in country. It will take some training and not just anyone will be able to work on it with out some education. Plugs and oil changes remain the same. You'll need a laptop and a dongle ($1087) to work on it or do computer updates. The Rotax computer program is unbelievable to what it can see within the engine and alert you to what is going on. The on board computer records everything 10 times a second for the life of the engine and records every single start and keeps a lo of all error codes. You won't be able to stretch the truth and say I didn't do this or that or that it just happened 1 hr ago because it's all recorded. No schools currently out for this engine. I had to go back to Nassau last Sept. for my class.

[RFSchaller]

"Had" to go to Nassau? WAZAMATTA, Roger, does your wife monitor this site?

You're not alone. I convinced my wife I "had" to go to Laughlin for an IPC and stay in the casino resort!

[roger lee]

You don't think she let me go by myself. LOL
Not a chance.
I told her I had to go and she said when are WE going. Go figure. LOL

I was supposed to go back this month, but it has been canceled until June -July and I doubt that will be by myself either.

[rv3flier]

I just made Tony's fixture to help measure prop pitch and used a digital level as described. I found one blade at 65.7* and the other at 66.3* a whopping .6* difference -- no wonder I'm getting vibration. My static rpm is 4700 +/-20. I was shooting for 66.5 degrees on both blades, but after an hour of fiddling, I ended up with 66.3* and 66.2*. Now the next item on the checklist is to ground run the engine at just under 2500 rpm (1/2 estimated static) for 5 min. I'm assuming that it's safe to run the engine without the spinner --- but since assumption is the mother of all errors, I'm double checking with those who've gone through the procedure before.

I'll probably have to do this again since an average difference of the before and after adjustment is only .25* and I'd like to get to 4950 rpm static.

TIA

John

[Jetguy]

Your on the right track, keep pushing ahead. If the pitot tube is installed you need the spinner, if not then it should be ok.