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Jan 26, 2019, 03:21 PM
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RIX : V22 Osprey Rebuild


Gentlemen :

I have been away for far too long and much has happened since my last posting . November saw a month long trip to Cairns Australia to visit my mate Dennis (cynr100) and the club mates with CMAC . This trip was a RC flying and touring trip of a lifetime . Regards to Dennis and the 'boys' who took me in as one of their own . Although I did not fly up to my old levels of competence , I did learn to fly ACRO on the 250mm quadcopter I took along with Dennis' help . He created a monster !

Recent winter shop projects are well along their way . Rebuilds of 2 quadcopters and a Trifecta build have been completed at this juncture . The latest rebuild is of my old V22 Osprey . I always had problems with this one with regards to the nacelle tilting mechs and their setup in the Happy Sundays firmware . A new design around a pair of bargain bin (HK) buggy type 2:1 gear ratio transmissions are at the heart of this . The basic idea is to use these gearboxes to each drive an 7mm fiberglas arrow shaft to do the nacelle tilting . A heavier duty MG995 servo will be used to connect to an intermediate jack shaft to drive the inputs of the gearboxes . Simple 3D printer type GT series gears and belts make the jack shaft to gearbox connections a snap . Future expansions may see a second servo be added to drive each gear mech . For now , I have both being driven with one servo .

All parts so far have been 3D printed for this project . Quick design changes can be realized in short order . At this point , the pix show the wing section for the center being populated with the other parts in a mock up mode . A couple more parts need to be designed to complete the servo connection .

It proved necessary to use a set of heavier / thick 3D printed drive gears for the servo to jackshaft part of this drive mechanism as belts would not be able to positively transfer the necessary torque of the servo thru to the nacelles . There will be a lot of induced gyroscopic stresses by each nacelle while in operation due to the motors themselves . (Procession and gyroscopic torques)

I believe that this type of tilting mech will be succesful to convert the 180 degree servo travel into the final 90 degree travel of the nacelle tilting drive shafts .

SEE UPDATED PIX as of January 29 / 19 .
SEE UPDATED PIX as of February 1 / 19 .

Reards to my mate Dennis and the members of the Cairns model flying club . Also my readers . RickC_RCAV8R
Last edited by RickC_RCAV8R; Jan 31, 2019 at 03:35 PM. Reason: sp
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Jan 29, 2019, 03:36 PM
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January 29 / 19 UPDATE PIX


Gentlemen :

I have printed off another part for the tilt mechanism that is the support structure for the jackshaft and timing belts(2) tensioning rods . I used some 5mm prop spacers to cewnter the shaft as seen in the pix . Servo mounts and perhaps a couple of 3D printed gears for the servo and jackshaft are being considered at this time to provide a positive throw thru-out the full 180 servo travel .

NOTE that it may be necessary to add in a belt tensioning shaft to allow for the free movement of the jackshaft and to take up the possible servo-to -jackshaft slack / slop . I tried a temporary fit of one and it does remove the slack .
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Jan 29, 2019, 09:39 PM
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RCvertt's Avatar
Interesting work. Good job.
Jan 30, 2019, 12:16 AM
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@Rcvertt :

Thanx mate . Having a 3D printer around DOES make for easy designs and prototyping . This mech is being designed as parts are fitted . At present , I am printing off the GT2 gears for the jackshaft as I ran out of aluminum ones . No worries though . While I am at it , may as well print off the set for the jackshaft / servo . All that would be left is a servo mount .

The tensioner shaft IS a must as it takes up the belt slop and makes any servo travel 'positive' with no lagging . So far , the mechanism is silky smooth in operation even with some minor mis-alignments along the way . Wing sections to come later will mate up with this central section . Now about designing a pair of nacelles . Hmmmmmmmmmm
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Jan 30, 2019, 06:16 PM
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cynr100's Avatar
This is looking awesome mate, I still can't see the whole picture but wait with baited breath to see all the bits connected.

Just looking at the wing platform will there be a wing lock pin cammed to the tilt servo so that the gear boxes don't get stuck with all the tension during normal flight?? just a thought

Edit: silly me, just had another look and remembered that only the nacelles will be tilting............
Last edited by cynr100; Jan 30, 2019 at 06:20 PM. Reason: dummy
Jan 30, 2019, 10:12 PM
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@cynr100 :

Thanx Denny ! This project is coming together nicely now as the last pair of GT2 belt gears and the servo / jackshaft ones printed last night work really well . Am printing off the servo mount and wing sections . The wing sections take about 7 hours apiece to do . 6 required . I designed those with built in bearings for the nacelle tilting drive shafts (fiberglass arrow shafts) . Doing the nacelle designing tonight .

How is Brizz mate ? Greetings for the wiff and Dad . Go shopping . hahahahahaha Love the rock debacle .
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Jan 31, 2019, 03:33 PM
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@cynr100 :

Denny , a few update pix (Feb 1 / 19) to better clarify the overall scheme I am using for the engine nacelles tilting . I believe that these should answer any questions you may have . As of today , 'on the bench' tweaking have hte first wing section installed and is seeing a silky smooth operation of the tilt drive shaft . Marvellous methinks ! The 'head engineer' upstairs is a great designer .
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Jan 31, 2019, 05:59 PM
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cynr100's Avatar
Brisbane................ahhh........hot and dry but home is coping a deluge.

Plan to visit a "shop" tomorrow just for a look I flew down this time so unfortunately no big boxes allowed on the return.

What tolerances are you expecting between the 10mm arrow shaft and bearings, the reason I ask is that AL tubing may resist torsion twist better.

Keep at it

Just checked the new pics..........................NICE>>!!
Jan 31, 2019, 11:33 PM
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@cynr100 :

Denny . Glad to see that you guys are having a great trip . Buy lots at the hobby shop !

7mm fiberglas shaft . I may have screwed up the specs befrore . Point 2mm extra clearances which are working just Ducky . Could use aluminum shafts , I guess , but getting them is a problem around these parts .

Printing off the servo mounting box at the moment . Did a couple more wing sections this afternoon and they turned out awesome too . The next batch of pix in a few days should see the wing assembled but not covered . Will have to do the ailerons next . Have a nacelle designed but have not decided on 'scaling' within CURA for a motor size yet . Will have to do some AUW calcs first . May as well print off the fuselage 2 piece wing saddle mount and cover lid in the meantime . Cheers mate .
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Feb 06, 2019, 04:15 PM
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Fellas :

Have the wing completely assembled as far as the 3D printed stuff goes and the tilt mech worx awesome . The wing IS a tad heavy though . Also , an initial 3D printing of the nacelles has been done and it is also heavy . With Dennis' (cynr100) help , I will be thinning the part walls in hopes of lightening them while retaining the central strengths . Nacelle parts have also been combined in more larger ones to drop the parts count . Down to 4 from the original 6 . All working well so far . Ran out of PLA ! A delay .
Last edited by RickC_RCAV8R; Feb 06, 2019 at 04:16 PM. Reason: sp


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