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Re: Sensenich Flight Test Report

PostPosted: Wed Feb 18, 2015 3:02 pm
by scubarider2
Jack, a couple questions please.
1. The Nord lock washers. They come glued together. Are they suppose to stay like that or should I peel them apart and reverse them. The picture in the instructions looks like they belong with ALL the grooves facing each other instead of just the few. No where does it say to do this but the picture is what is throwing me.
2. Take a look at the picture. My spacer is WAY too big with almost 2 inches to the cowling. The spinner measurements was what I went by on my old Warp and that is what caused me to go larger. The Sensenich spinner is flush. Looks like I could use the 1/2 to 3/4in spacer vs the 1.775 one sent to me. Would it be possible to send back everything behind the prop and go with a different spacer size, bolts, etc?
3. Thanks for all your help on this Jack!
Dennis

Re: Sensenich Flight Test Report

PostPosted: Wed Feb 18, 2015 4:59 pm
by Jack L
Dennis,

You definitely need a thinner spinner! Don't worry about the confusion in measuring.

Call me.

Jack L

Re: Sensenich Flight Test Report

PostPosted: Thu Feb 19, 2015 2:52 pm
by scubarider2
Dang! Sensenich is a great company. Thanks Jack and Charley. Called and told them "I" measured wrong due to a weird spinner tail that I got from Warp Drive Props. The Sensenich is flush against the base. So all I did was call and they have the proper one already on the way. They will credit my account when they receive the old one back. Great customer service! :mrgreen: :mrgreen: :mrgreen:
Dennis

Re: Sensenich Flight Test Report

PostPosted: Tue Feb 24, 2015 9:22 pm
by scubarider2
Went to the hangar this evening and mounted the prop after getting the right size spacer. We are at 2 inches of snow right now and they are calling for another 6 by tomorrow. *sigh* Can't test it out. But right now I am getting right at 105mph cruise at 5200-5300rpms. I figure with the new prop I will get 225mph at 5000-5200rpms. What do you think? :shock:
Dennis

Re: Sensenich Flight Test Report

PostPosted: Tue Mar 03, 2015 11:40 pm
by av8rps
Dennis,

Your new prop sure looks good on your airplane. I look forward to hearing how it works.

If it works half as good as it looks, you just might get that 225 mph :wink:

Paul

Re: Sensenich Flight Test Report

PostPosted: Wed Mar 04, 2015 10:39 pm
by scubarider2
I like the way you think Paul. The weather here has been terrible for flight testing. Hopefully this weekend and will give a report. :mrgreen:
Dennis

Re: Sensenich Flight Test Report

PostPosted: Fri Mar 13, 2015 4:30 pm
by scubarider2
Ok it has either snowed, iced, rained or had 25+mph winds here in North Georgia for the last month. :x
I did get the plane up with the new Sensenich prop once. I had some trouble trying to get the pitch set right so finally chuncked the pins and did it myself. So now at WOT take-off I am getting 5200rpm. The weather has not been still enough to really get some numbers but my first impression of the prop versus the Warp is that the Sensenich puts me in the air faster and climbs better. I am so far disappointed in the cruise. I thought I would get a little more but got nothing. Not even 1mph faster. But I did not loose any cruise with better climb performance. Numbers are coming soon. Still raining... *sigh*
Dennis

Re: Sensenich Flight Test Report

PostPosted: Sat Mar 14, 2015 11:31 am
by av8rps
Dennis,

Too bad about the weather. Thar's got to be driving you crazy having a new toy to play with.

Based on your preliminary results, it sounds like you will need to change pitch abit to get your cruise up. I would probably first try a setting that will allow for 5800 at WOT straight and level to see where that puts you. That will most likely represent your fastest speed of your engine and prop combination, and then with the power pulled back to 5500 for max continous power, that should give you a good cruise speed number while still providing a short takeoff and a good climb.

But if you are more interested in cruise than climb, you might want to adjust it for something between 5500 and 5700 (WOT straight and level). I know that from adjusting my IVO in flight adjustable that I use on my 912 powered Kitfox. Granted I am just moving a switch vs you adjusting with a wrench and angle gauge, but when you get it where you like it best I believe you're going to like that Sensenich. Even if performance was just the same as the warp, your gearbox will appreciate the Sensenich.

Re: Sensenich Flight Test Report

PostPosted: Sun Mar 15, 2015 9:00 am
by scubarider2
That confuses me somewhat. I thought the best way to get the best cruise is to dial in the most pitch possible but not to fall below 5200rpm at takeoff? Less pitch gives me better takeoff performance with loss of cruise. :?:
Dennis

Re: Sensenich Flight Test Report

PostPosted: Sun Mar 15, 2015 9:15 am
by MarkZ
Just from my perspective, limited in Rotax experience, the max rpm is 5800 for 5 minutes. If the throttle cable fails you go max RPM. We adjusted the prop for WOT to be no more than 5700 RPM. If I have a throttle cable fail I'm going to have options with power. If someone has a better idea, I'm all ears.

Re: Sensenich Flight Test Report

PostPosted: Sun Mar 15, 2015 4:26 pm
by User GDS
Another consideration besides prop efficiency is engine output, the difference between 5300 and 5800 is about 5%:

Image


I highly recommend a dynamic prop balance, too, it made a huge difference with my warp drive.

Re: Sensenich Flight Test Report

PostPosted: Mon Mar 16, 2015 1:00 am
by av8rps
Sorry if I confused you Dennis. My suggested approach to adjusting your prop for best speed is just from what I have learned by playing with different pitches and rpms with my inflight adjustable IVO on my 912 Kitfox. And while I agree that the hp difference between 5300 and 5800 is not that much when looking at the Rotax chart, I can assure you there can be a big difference in overall cruise speeds in those rpm ranges.

One of the most important things I've learned by playing with that IFA prop is that overpitching the prop on a 912 so as to not allow at least 5500 rpm (WOT when straight and level) will actually destroy the potential for getting max top speed. Personally I believe a really good rpm setting for a 912uls Highlander would be 5,650 max rpm. That will allow one to pull back power just ever so slightly so that with just a slight power reduction you can run at 5500 max continuous rpm for top speed, with no concerns of being in that 5 minute limited rpm range.

I understand the 5200 min rpm Rotax wants for takeoff, and agree that is a good place to start with your prop adjustment testing. But I think if you focus more on the WOT straight and level numbers I'm suggesting you will get a better top speed.

Of course, that is if your weather ever cooperates long enough for you to play with your new prop. :wink:

scubarider2 wrote:That confuses me somewhat. I thought the best way to get the best cruise is to dial in the most pitch possible but not to fall below 5200rpm at takeoff? Less pitch gives me better takeoff performance with loss of cruise. :?:
Dennis

Re: Sensenich Flight Test Report

PostPosted: Mon Mar 16, 2015 5:49 pm
by Jack L
Guys, all of this discussion is interesting and there is so much to learn.

Dennis as we discussed you are on the right track as the Rotax Service Letter SL-912-016 states that take off RPM at WOT should not be below 5200 RPM to avoid overloading the engine. Having said that I agree with Paul in that you really need a calm day to get up to altitude to test your WOT RPM in straight and level flight and to carry out proper ground speed testing to compare the Warp to the Sensenich. I would also ensure that your tach is accurate, I used my RC tach and multiplied the value by 2.43 for a comparison and found that my aircraft tach was accurate. I hope that you get good weather soon and that you can find the sweet spot for your propeller.

Mark, on page 5-3 of the Rotax Operators Manual it states that Engine Speed over 5500 RPM is restricted to 5 minutes so if the throttle cable breaks anything over 5500 RPM allows you 5 minutes to land without worrying about the engine. If it happened to me I would just do what I have to do to get down safely and worry about the engine later.

GDS, where did that graph come from? I cannot find it in my Rotax 912 documentation and what I find interesting is that the letter "A" represents takeoff. It is interesting that the letter "A" is sitting at 87HP which is produced at 4800 RPM on the graph? Just curious.

Jack

Re: Sensenich Flight Test Report

PostPosted: Mon Mar 16, 2015 11:55 pm
by av8rps
If my throttle cable breaks, I'm going to take that opportunity to climb, climb, climb until I get directly over the place I want to land and then kill the mags and glide down to a nice soft dead stick landing.

I used to practice dead stick landings from as high as 9k agl in my old Avid Flyer, so doing one for a true emergency would be no big deal. I also used to log my engine off flying time (3.8 hrs total) and landings (31) but stopped after the airport manager expressed concerns that it was wreckless. I never saw it anymore wreckless than if operating a glider, but out of respect for the airport manager I stopped doing it there. After that occasionally I would still practice real dead sticks, but only at a local grass strip, or at the lake when on floats.

I think we should all know how to fly our planes with the engine off. It could be lifesaving.

Re: Sensenich Flight Test Report

PostPosted: Tue Mar 17, 2015 8:12 pm
by scubarider2
Thanks guys for all the advice. We continue to have weather issues here. Today was beauuuutiful except for the 20+mph winds :? I can't wait to get up there and play with the new prop some more and get some better numbers compared to the Warp. Fingers crossed soon...
Dennis