Protos super stretch question

[kavic5150]

So I'm getting my ducks in a row and planning to stretch a Protos 500 to run 550mm blades. But I've hit a snag. I havent managed to find any 550mm blades with a 10mm root, they're all 12mm these days.

Anyone know of 550s with a 10mm blade root?

If nothing else I've got an X5 flybar head I can use, but I'd like to do this build with MSH stuff.

Also what do you guys think about 550mm blades and the stock feathering shaft just for sport flying? Bad idea?

[Outlaw10.5]

I haven't seen 10mm root beyond 515mm. Thats what the stretch compass atom's run.

[TitaniumFreak]

so far this is where I`m at with 515 .. the feathering shaft worked fine with mine but I had issues with the plastic blade grips longstand ball links breaking . I was using 515kbdd blades which are wide cord . that's my reason to find the rails r-516 but are hard to find . ive thought downsizing to sab 500. but I`m set to go 515 . my next step is to either mill out the blade grips for 12mm so it will widen my choices for blades . in this picture ive got 430mm kbdd mounted with extended tail .

[maG69]

please can you post some details about the longer boom (size, manufactor, where to by....and so) and also about the longer belt.

im wanna also super stretch it... great job so far.

Is the stock stretch boom capable to run 500mm blades ?

[sp00fman]

kavic5150, If you want i could see if the plastic hurricane 550 grips will fit the protos hub. It is 5mm fs by design.

One possible problem you will face is gearing. you might not find a pinion small enough to stay on 6s lipo's, or you have to find an even lower kV motor.

[kavic5150]

I've been shopping around for a motor that weighs around 280 grams and spins at 550 to 600kv.

[TitaniumFreak]

kavic 5150 are you going with the 17mm boom ?

[kavic5150]

Yes. Found some on ebay.

http://www.ebay.com/itm/321349607509...%3AMEBIDX%3AIT

And the motor I'm considering.

http://www.modellhobby.de/Engines-and-motors/Electric-motors/DYMOND-brushless-motors/Outrunner-motors/DYMOND-Master-HQ-4252.htm?shop=k_staufenb_e&SessionId=&a=article&Pr odNr=03121726&t=11&c=3258&p=3258

[kavic5150]

Originally Posted by maG69

please can you post some details about the longer boom (size, manufactor, where to by....and so) and also about the longer belt.

im wanna also super stretch it... great job so far.

Is the stock stretch boom capable to run 500mm blades ?

I dont think 500mm blades would work on a stock stretch. For timing belts, check here:

https://sdp-si.com/eStore/Catalog

The stock Protos belt has 448 teeth, a total pitch length (distance between belt teeth * number of teeth) of 1344mm is 4mm wide and has an HTD tooth profile. The part number 3M-1344-4 is printed on the outside of the belt.

So if you want to use 500mm blades, look for a 4 or 5mm wide HTD belt. Adding 80mm to the blades means 80mm more tail boom and a 1504mm or so belt.

If you cant find a suitable HTD belt you could possibly get away with using a GT2 belt. The specs are very similar.

[bgymr]

I want to make my protos 12s and haven't been able to find a motor. I bought an old lipotech to rewind, but can't get the darn stator to budge. Kentronic quit making the motor that fit. The one you listed may be a good option!

Thanks!

[bgymr]

If the stock belt is 1344, and you add 80 to teh boom, I would think the new belt should be around 1504mm.

I can't imagine this thing streteched, its already floaty!

[kavic5150]

Originally Posted by bgymr

I want to make my protos 12s and haven't been able to find a motor. I bought an old lipotech to rewind, but can't get the darn stator to budge. Kentronic quit making the motor that fit. The one you listed may be a good option!

Thanks!

Be careful. Those motors are only rated to 1100 watts. The stock motor is rated to 1450. Also those are airplane motors. Its a good bet they have a higher pole count. Probably 14 poles while the stock motor has 10. This will work an esc harder since it has to commutate faster.

Originally Posted by sp00fman

kavic5150, If you want i could see if the plastic hurricane 550 grips will fit the protos hub. It is 5mm fs by design.

Thanks for the offer Spoofman. I've got Hurricane 550 grips and X5 grips here if I decide to go that route.

[dr dremel]

Originally Posted by bgymr

...I bought an old lipotech to rewind, but can't get the darn stator to budge...

Have you tried putting it in the oven? I had a stubborn stator/holder and after 10Min@200deg C in the oven I wrapped it in a towel and had a go with large pliers. One has to be careful not to damage the stator stack in the process, but the glue finally came loose enough to turn it from the stator holder.

[kavic5150]

Originally Posted by bgymr

If the stock belt is 1344, and you add 80 to teh boom, I would think the new belt should be around 1504mm.

I can't imagine this thing streteched, its already floaty!

Thanks. Fixed my math mistake. You'd think I would know this by now since this will be my 3rd stretched bird.

[kavic5150]

Almost there.

I have most of the necessary parts and I've just emailed SDP-si.com to get those 6mm wide belts cut down to 5mm. Hopefully they wont charge me a small fortune to have this done, the belts are $12 each and I only want 2 of them for starters.

Also have 3 cyclic servos, motor, the CF tube, a couple of 6s packs, and the plastic frame parts to use frame sides. Not CF frame sides, I'll be using some home made 3mm acrylic ones like on my non stretch.

What I'm seriously thinking of doing is paying someone to make an integrated, one piece bearing block that combines the motor mount and 3rd bearing block. That way the torque will not flex the frame as much. Those 2 parts arent lined up straight so it would require some bending too, but it shouldnt be too complicated.

Of course I'll be using the 3rd bearing support on the motor. And I got a set of the "Astroid Designs Carbon Motor Mount Inserts." Thanks to Bill from MSH-direct.com Those will help distribute some of the stress around the motor mount even though I'm using plexiglass.

So not much left on my shopping list. Just the 3rd bearing support, a used CC Ice or Edge 75 or 100, and either of these for a bling tail servo, havent decided:

https://www.spektrumrc.com/Products/...odID=SPMSH6200

or

http://www.ebay.com/itm/ABDS-997HTG-...item417f849fe6

[kavic5150]

One used Ice 75 arrived today. And I've ran into a bit of a snag with the stretch belt.

I decided to err on the side of caution and go with a 1665mm total length belt. That way I can run 85 or 95mm tail blades and hit some really low head speeds.

The problem is I cant get a reply from SDP-si.com about cutting the belts down to 5mm. Is there room for a 6mm belt? Somehow I doubt it would work well. The pinion, main gear and tail gear might accomodate 6mm, but those guide pulleys would just end up getting chewed.

I dont want to resort to a direct drive setup. That would just add weight to the project with another esc and smallish tail motor. But I'll do it if I need to just to get this thing off the ground.

[TitaniumFreak]

I just went and measured mine and it came in at .208 or 5.28mm and that is really about all it can take on the width. I did try a 6mm belt and it was squeezing in the alluminium pulleys adding a little drag . not sure if the plastic ones are wider?

I tried your link on that belt and it looks like the site is down ? security cert.

http://shop.polybelt.com/1569-3M-05-...9-3M-05BNG.htm is the belt I am using . The next size up is 1800-3M

[kavic5150]

Not sure why that is, I got the same message. Just use the front door then.

http://www.sdp-si.com/

Then click buy online, and select metric, then click belts and cables. Under that, click timing belts.

[kavic5150]

Just an update, I got nowhere with SDP-si.com. They are great for ordering things right off the shelf, dont get me wrong. But they havent given me a solid reply to 4 different emails now. I guess I dropped the ball when they asked my company name. Maybe I should have made something up?

Just by accident the other day I stumbled across a great solution for a tail belt.

http://www.helidirect.com/hd-cell-50...-5-p-33545.hdx

It just arrived today. 5mm wide with a pitch length (space between 2 teeth x total number of teeth) of 1692mm.

S3M belts have a very slightly different tooth profile than 3mm GT2 but will easily mesh with the Protos gears. Its slightly flatter on the top of the tooth but the specs are the same otherwise.



I should have plenty of room for 95mm tail blades. And the grips on the Lynx tail case are built for tail blades with 5mm roots.

[Jomaba4308]

Originally Posted by kavic5150

Just an update, I got nowhere with SDP-si.com. They are great for ordering things right off the shelf, dont get me wrong. But they havent given me a solid reply to 4 different emails now. I guess I dropped the ball when they asked my company name. Maybe I should have made something up?

Just by accident the other day I stumbled across a great solution for a tail belt.

http://www.helidirect.com/hd-cell-50...-5-p-33545.hdx

It just arrived today. 5mm wide with a pitch length (space between 2 teeth x total number of teeth) of 1692mm.

S3M belts have a very slightly different tooth profile than 3mm GT2 but will easily mesh with the Protos gears. Its slightly flatter on the top of the tooth but the specs are the same otherwise.



I should have plenty of room for 95mm tail blades. And the grips on the Lynx tail case are built for tail blades with 5mm roots.

What size mains will you use with that belt? I have been following this thread because I want to stretch but there are only a couple 470mm blades so I would like to try 500mm blades with more options.