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Blueadventures

Propeller pitch adjusting tool

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This weekend I was needing to adjust my prop on the Nynja's R912 to be between 5,500 and 5,600 rpm. It was at WOT level flight 5,375 rpm then recently re-pitched to 19 deg giving WOT 5,750 level flight. To redo the pitch I needed a better tool so I made the following and it seems to work great. It certainly allowed good judgement of the pitch angle degree.

 

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372832724_Position20cmin20170501_095044.jpg.7d3a5d91c15c9f88cab420bc490c4484.jpg

 

 

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For what it's worth, Vans recommend using a digital level and home-made bracket to get the RV-12 blade angles to match to +/- 0.1 deg.

 

upload_2017-5-1_18-33-41.png.ad52a034515dc8008493cbed72d02c32.png

 

upload_2017-5-1_18-33-17.png.ae4ae9b04b89736d8311351e5f143116.png

 

upload_2017-5-1_18-32-48.png.eb03fe2aaaf738dbefb76d5157634ff7.png

 

 

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Thanks. I have a cube digital. But found recently it seemed to at times go off its calibration. On the glass bubble i place a nico pen dot either end of the bubble to verify the spot. Then I can run over with the digital gauge when nipped up.

 

 

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Well done Blueadventures - great to see someone using their initiative.

 

I use an off the shelf digital level/protractor (double sided taped to a piece of aluminium that gives me a nice straight edge & spans the blade), Warp Drive protractor, builders bubble level, meter long steel rule, masking tap and ultra fine Sharpie. Some of the items are for course setting, to be followed by fine adjustment. Some are unnecessary duplication that works for me. All together I find I am able to make very fine repeatable adjustments that satisfy the "analy retentive" inner me. I cant be doing to bad a job, as I received a compliment on the accuracy of my settings from SuperAir, Armidale (head swollen out of all proportion)

 

 

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An app called TiltMeter for the iPhone gives one tenth degree accuracy. Works fine for me. Measure both ways to ensure no calibration error.

 

 

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Use a small line laser clamped to the back of the prop, facing the ground, the extra distance make very fine adjustments obvious, on a cement floor can see differences well below that seen on an inclinometer

 

the line makes sure its sitting in the same spot on each blade assuming aircraft doesnt move.

 

 

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Well done Blueadventures - great to see someone using their initiative.

I use an off the shelf digital level/protractor (double sided taped to a piece of aluminium that gives me a nice straight edge & spans the blade), Warp Drive protractor, builders bubble level, meter long steel rule, masking tap and ultra fine Sharpie. Some of the items are for course setting, to be followed by fine adjustment. Some are unnecessary duplication that works for me. All together I find I am able to make very fine repeatable adjustments that satisfy the "analy retentive" inner me. I cant be doing to bad a job, as I received a compliment on the accuracy of my settings from SuperAir, Armidale (head swollen out of all proportion)

Hi SkippyD. Thanks for the detail. I made a Prop pitch tool because the digital cube one I had was playing up a bit recently (After calibrating and then doing a measure and resting the gauge I would find the reading back at the refference locationwoul be out buy 0.2 to 0.6 degrees - Was very frustrating and annoying as the least); I tried to source an adjustable protractor prop tool from US but could not arrange it soon enough so I decided to try making a home made one. And the home made tool worked great. My Nynja's DUC prop now at 20 degrees was at 19 deg. I have used a fine nico pen to mark the bubble location so the level is more accurate. Flew Wednesday morning. Nynja speeds are WOT level 5600rpm 98kts; 5,200 - 95kts; 5,000 - 92kts; 4,800 - 86kts; 4600 - 82 kts. Have prop sorted spot on now. I'm looking forward to a small increase in economy fuel wise on long trips. My next job is to give the outside a wash ready for some trips. Next year I aim to get one of those dynamic propeller testers and add that to my tool kit. Regards

 

Mike

 

 

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Use a small line laser clamped to the back of the prop, facing the ground, the extra distance make very fine adjustments obvious, on a cement floor can see differences well below that seen on an inclinometerthe line makes sure its sitting in the same spot on each blade assuming aircraft doesnt move.

I'll do that. Sounds like a great idea. Thanks. Mike.

 

 

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Wondering if anyone knows where you can buy these Pitch gauges from or has one for sale. I have done a seach and have come up empty.

 

Couldn't get the second photo to load showing the actual gauge.

 

Cheers Guy.

 

20170322_122855.jpg.201f06a007fb8aaf936885586051c807.jpg

 

 

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Manage to resize and here it it's 001_smile.gif.2cb759f06c4678ed4757932a99c02fa0.gif

 

20170322_122903.jpg.e81b2562a3f1df162424cc378ae6876c.jpg

 

 

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Manage to resize and here it it's 001_smile.gif.2cb759f06c4678ed4757932a99c02fa0.gif

Guy I got my tool the same as that from Ole at AAK at Taree when I built the hornet so he would probably be able to point you in the right direction.

 

Having said that jets idea of the laser pointer is a good one and is a lot more accurate. I was taught to secure the plane then use the laser pointer pointer at the roof(the floor makes more sense for marking it and keeping track but the distance to the roof will give you better accuracy) and then measure the prop tip height off the floor to ensure accuracy between blades.

 

 

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Guy I got my tool the same as that from Ole at AAK at Taree when I built the hornet so he would probably be able to point you in the right direction.

Having said that jets idea of the laser pointer is a good one and is a lot more accurate. I was taught to secure the plane then use the laser pointer pointer at the roof(the floor makes more sense for marking it and keeping track but the distance to the roof will give you better accuracy) and then measure the prop tip height off the floor to ensure accuracy between blades.

Agree. If I could have bought one I would have got it. I tried about a month before my first post but no reply about shipping cost or availability so could not progress an order. I would highly recommend adding the laser pointer to them if you have or get one.

 

I added Jets laser pointer idea to the tool I made. Will not bother buying a shop one now. I did try to source a warp drive tool but did not get reply so made my own tool. Was accurate with out the pointer and the laser pointer verifies / ensures precision of the blades pitch angles being equal. Cheers Mike

 

 

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Manage to resize and here it it's 001_smile.gif.2cb759f06c4678ed4757932a99c02fa0.gif

Warp Drive Propellers, Blade Pitch Setting, Warp Drive Professional Protractor

 

Personally, I use one of these..... Competition Aircraft | Ultra-Props and Propellers for Ultralight Aircraft

 

In this day and age you can't beat digital accuracy...

 

 

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Bolly make a gravity pointer one too but the lone laser works better i reckon

 

 

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All great ideas - but a few words of caution:

 

Pitch adjustments should be made with reference to a fixed part of the aircraft (not the floor,roof or airframe) preferably the prop hub or an accessible part of the engine.

 

Reasons - engine mounts and undercarriage flexes, the whole aircraft can move.

 

Movement WILL occur as you turn over the prop to adjust the next blade.

 

If you are referencing a part of the aircraft or its surroundings that can not be relied upon to remain constant (throughout the adjustment procedure), you run the risk of diminishing the the accuracy/repeatability for each prop and/or ability to easily make your adjustments .

 

In my case, I do all my adjustments by "zeroing" my measuring tools against the prop hub for every blade, after bringing each blade to the same rotational position.

 

I use my meter long builders level, against the hub bolts, to bring each blade into exactly the same horizontal position, in preparation for adjusting of the blade.

 

I use the level again after the adjustment to check the blade has not rotated (even slightly) during the procedure.

 

I also recheck my angles after final torquing of hub/blade root securing bolts (if out, I start again).

 

If you are finding it difficult to smoothly move the blade(s) - try coating the blade root/socket with Carnauba wax polish. The very slight lubrication qualities of the Carnauba will allow a "snug" blade to rotate smoothly.

 

Blueadventures - are you running a Rotax 912 ? If so, I am concerned that your focus on WOT may be impacting negatively on your climb out RPM (minimum 5200, better to be higher) - if not a 912, forget I said anything.

 

 

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All great ideas - but a few words of caution:

Pitch adjustments should be made with reference to a fixed part of the aircraft (not the floor,roof or airframe) preferably the prop hub or an accessible part of the engine.

 

Reasons - engine mounts and undercarriage flexes, the whole aircraft can move.

 

Movement WILL occur as you turn over the prop to adjust the next blade.

 

If you are referencing a part of the aircraft or its surroundings that can not be relied upon to remain constant (throughout the adjustment procedure), you run the risk of diminishing the the accuracy/repeatability for each prop and/or ability to easily make your adjustments .

 

In my case, I do all my adjustments by "zeroing" my measuring tools against the prop hub for every blade, after bringing each blade to the same rotational position.

 

I use my meter long builders level, against the hub bolts, to bring each blade into exactly the same horizontal position, in preparation for adjusting of the blade.

 

I use the level again after the adjustment to check the blade has not rotated (even slightly) during the procedure.

 

I also recheck my angles after final torquing of hub/blade root securing bolts (if out, I start again).

 

If you are finding it difficult to smoothly move the blade(s) - try coating the blade root/socket with Carnauba wax polish. The very slight lubrication qualities of the Carnauba will allow a "snug" blade to rotate smoothly.

 

Blueadventures - are you running a Rotax 912 ? If so, I am concerned that your focus on WOT may be impacting negatively on your climb out RPM (minimum 5200, better to be higher) - if not a 912, forget I said anything.

Hi SkippyD Engine is 912ULS2. Originally Climb out was 5,300rpm and WOT level was 5,375rpm. I then readjusted prop and it was then climb out at 5,650rpm and WOT level 5,750rpm - prop pitch 19 degrees full throttle;if connection fails.I needed to reduce WOT rpm.

 

My target rpm WOT level was 5,500 min 5,600 rpm max. Currently with Prop at 20 degrees climb out is 5,500 and WOT level is 5,580 rpm (Tad under 5,600 on tacho.) I agree about 5,200 not being satisfactory for even WOT level; as rotax say if only 5,200 then back of atleast 100rpm to ensure no damage occurs to engine. I am leaving the pitch where it is now.

 

I have a digital cube tool and a mate has one also. Over time I have seen that at times they have small errors in their calibration; this throws out the adjustment accuracy and is frustrating. The digital cube did work well for a while and then played u; I hope all those that have and use a digital cube do not experience what I have just described. I reference off the prop hub and had thought about setting up a side reference the same angle as the prop hub so that during the process I could check / verify or recalibrate the digital angle cube to ensure correct angle measurement. But I made up the tool in the posted image and it works great.

 

Next year I plan to buy a dynamic prop balancer for my tool box.

 

Thanks for your concern, let me now if I'm missing something.

 

Regards

 

Mike

 

 

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I like those specs Mike, very nice.

 

I had a bloke ask me what fuel usage I got at 4800. I said I have no idea, I would never run my engine consistently there.....

 

 

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All great ideas - but a few words of caution:Pitch adjustments should be made with reference to a fixed part of the aircraft (not the floor,roof or airframe) preferably the prop hub or an accessible part of the engine.

 

Reasons - engine mounts and undercarriage flexes, the whole aircraft can move.

 

Movement WILL occur as you turn over the prop to adjust the next blade.

 

.

If you drop a spark plug out of each cylinder you should be able to turn the prop without moving anything else.

 

 

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Thanks Downunder and SDQDI and others for the reply and I'm onto it 001_smile.gif.2cb759f06c4678ed4757932a99c02fa0.gif

 

 

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If you drop a spark plug out of each cylinder you should be able to turn the prop without moving anything else.

I would say less likely to move but why not just use a reference point that is guaranteed not to move, in relation to the prop measuring locations ?

 

 

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Hi Mike - Sounds like you have the whole prop pitch/ engine RPM relationship under control. Well done!

 

Regarding the Dynamic Prop Balancer - I would also like one BUT my concern is that good ones (by reputation) would seem to be quite costly. This is a tool that should only be needed infrequently by each aircraft.Its investment may be easier to justify over several. Might be better bought by a Club with a few individuals trained as user/operators. When I wanted the service of one, couldnt find a provider (club, individual, professional) in the Sydney Basin - I ended up flying to Armidale. Happy with the excuse to fly and with the service provided.

 

 

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Hi SkippyD Engine is 912ULS2. Originally Climb out was 5,300rpm and WOT level was 5,375rpm. I then readjusted prop and it was then climb out at 5,650rpm and WOT level 5,750rpm - prop pitch 19 degrees full throttle;if connection fails.I needed to reduce WOT rpm.

My target rpm WOT level was 5,500 min 5,600 rpm max. Currently with Prop at 20 degrees climb out is 5,500 and WOT level is 5,580 rpm (Tad under 5,600 on tacho.) I agree about 5,200 not being satisfactory for even WOT level; as rotax say if only 5,200 then back of atleast 100rpm to ensure no damage occurs to engine. I am leaving the pitch where it is now.

 

I have a digital cube tool and a mate has one also. Over time I have seen that at times they have small errors in their calibration; this throws out the adjustment accuracy and is frustrating. The digital cube did work well for a while and then played u; I hope all those that have and use a digital cube do not experience what I have just described. I reference off the prop hub and had thought about setting up a side reference the same angle as the prop hub so that during the process I could check / verify or recalibrate the digital angle cube to ensure correct angle measurement. But I made up the tool in the posted image and it works great.

 

Next year I plan to buy a dynamic prop balancer for my tool box.

 

Thanks for your concern, let me now if I'm missing something.

 

Regards

 

Mike

To resurrect an older thread and for my education as I am new to Rotax engines.

 

On Sunday we re-pitched our Savage Cub (Rotax 912 ULS with three blade DUC Helices ground adjustable prop). On climb we were getting 5,200 rpm max before making the prop 1 degree finer and now we are getting 5,400 rpm on climb (performance improvement was stunning). I am yet to test max throttle rpm at straight and level as the weather became unsuitable.

 

We want max takeoff performance and good engine safety as well. Do I have it right, that we are aiming for probably about 5,500rpm on take off and most importantly about 5,650 rpm WOT in straight and level? Airfield is about 800ft above msl, should the test be carried out at sea level to be sure? Does the 800ft make enough difference to be concerned about?

 

I have also read to cruise anywhere between 5,000 and 5,400 rpm, as below that you are labouring the engine (fine for circuits and landings but cruise, keep it higher).

 

Thanks in advance.

 

 

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To resurrect an older thread and for my education as I am new to Rotax engines.

On Sunday we re-pitched our Savage Cub (Rotax 912 ULS with three blade DUC Helices ground adjustable prop). On climb we were getting 5,200 rpm max before making the prop 1 degree finer and now we are getting 5,400 rpm on climb (performance improvement was stunning). I am yet to test max throttle rpm at straight and level as the weather became unsuitable.

 

We want max takeoff performance and good engine safety as well. Do I have it right, that we are aiming for probably about 5,500rpm on take off and most importantly about 5,650 rpm WOT in straight and level? Airfield is about 800ft above msl, should the test be carried out at sea level to be sure? Does the 800ft make enough difference to be concerned about?

 

I have also read to cruise anywhere between 5,000 and 5,400 rpm, as below that you are labouring the engine (fine for circuits and landings but cruise, keep it higher).

 

Thanks in advance.

Hi Damiens -

 

Disclaimer - I am a "bush" mechanic of some 50+ years. I have a PPL 25 years, RAA Cert 9 years and have owned a Rotax 912 ULS motivated ATEC Zephyr for about 8 years also. I am far from being an expert on the matter you have enquired about but do have some experience (on my own aircraft) which may be of assistance.

 

My home strip (1,100 ft amsl ) is very demanding, so I have my two blade prop pitched toward a climb advantage (not max climb) - NOTE I do not take passengers into/out of my home strip but frequently carry max load (fuel & camping gear).

 

I get 5200 rpm @ well over 1000 ft/min climb out and about the same for a full power static run up. I believe this to the the Rotax minimum recommended rpm under climb load.

 

As airspeed builds, I have to either increase climb angle or throttle back to stay within Rotax recommended rpm (engine speed & time limits)

 

I like to cruise at 4800 - 5200 rpm. This gives me an indicated air speed of 100 - 110 knots (depending on altitude) and a fuel flow of from less than 13 - 14 LPH.

 

My aircraft can "loiter" 50-70 knots @ 7-8 lph with the engine doing somewhere in the 4000 +/- rpm range

 

I rarely go above the the cruise figures but every now and again we will do a 5400 or more rpm - air speeds can go over 120 knots but fuel burn is correspondingly higher in the 18 +/- LPH range.

 

My WOT is @ the top of the yellow arc, so can only be sustained for 5 mins or so - I dont go there except to do a brief test..

 

If my home strip had a flatter (500 fpm) departure and approach, I would adjust my pop accordingly for better (higher air speed for given rpm and possibly better trip economy) cruise performance.

 

Your aircraft has the "look" of a fairly high drag airframe so you may be optimizing its STOL performance - should this be the case your figures look pretty good. If you want to improve cruise there would appear to be room to "corsen" the prop a little.

 

I have found that using accurate devices (with good repeatability) and obsessive attention to detail (check, recheck & recheck again) to set pitch angle pays off with better performance, smooth running and ultimately hopefully longer lasting engine/prop.

 

Only you can decide what the objectives are regarding engine speed / aircraft performance and set your prop accordingly.

 

 

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