ebay accident- Mini Protos lightweight project

[dr dremel]

Found some time on the WE to get the wiring done. Before that I had to mount the Hitec servos and do the alignment of the 3 main bearings.

Here is were the EZO main bearings came back to bite me, as they have less play than the stock bearings. This gave me a lot less margin of error for the positioning of the bearing blocks in a way that the main shaft falls through all 3 bearings. Eventually I made it, but there are probably better areas to use these bearings.

Cables are shortened where possible, but I left the esc cable alone (couldn´t get myself to cut up the new YGE cable). I also added a small piece of anti vibe foam where the cables may touch the heli frame. I found this on my other MiniP to be essential to get the vibes down in the VBar analyzer.

I highly recommend to take off the bottom plate for doing the wiring, makes things very easy.

[MiataJohn]

Looks nice. Now I have to rewire mine so it looks neater.

[dr dremel]

Originally Posted by MiataJohn

Looks nice. Now I have to rewire mine so it looks neater.

Thanks, I think the Mini Protos is quite easy to get the wires tucked, lots of provisions for zip ties in the frame.

I see in your sig that you have the JR 290 tail servo on your Mini, how does it work for you?
At 7g claimed weight this would save me another 14g.

[MiataJohn]

It worked well for my flying style (just driving it around, no smack). Have had a continuous tail wag that I have been chasing so I put an Align 425 on it but no help. It already has the Lynx tail slider and pitch lever so I'm thinking maybe a little binding even though it feels smooth. Will have to try spooling it up without main blades and working the tail pushrod by hand. The 290 is a nice servo which also worked well on my Blade 400.

[jmtyndall]

Do that carefully. That tail can generate LOADS of thrust

[MiataJohn]

Thanks for the heads up, but I clamp it down. Got bit by the tail blades on my B400 once and that was enough,

[dr dremel]

Thank you MiataJohn for your feedback, although it does not sound too encouraging to try this servo. I´m far from being a smack pilot, but do throw my helis around quite a bit. I think I´ll try the current setup first. FWIW: On my other MiniP I have a mini (not micro) Savöx tail servo and it´s as solid as it can be.

I´m setting up the head right now and unfortunately the break away servo arms I got to save the supposedly weak HiTec gears in a crash are way too short to get good geometry. The manual calls for 15mm ball distance on the cyclics, these are 13mm at best.

[dr dremel]

Also couldn´t help to live up to my nickname

Totally not worth the effort for 2g saved though.

[jmtyndall]

If you wanted to get crazy you probably don't need a bottom tray per say, as long as you have enough material where the screws go in to provide lateral support

[dr dremel]

Yep theoretically one could chop away the whole bottom tray and frame and end up with something like the Protos Extrem:



But that means a lot of fab work for the landing gear. Also no boom supports, so maybe a reinforced boom. I´d also be afraid of rough landings damaging the motor.

[jmtyndall]

Woah! That's more extreme than I was thinking

[dr dremel]

I bought some new packs and shortened the cables quite a bit this time. I´ve run the batt cables coming out from the top of the battery tray until now, running down one side to the esc. To cut down on cable length I decided to turn the batts around and also shorten the esc cables. But the short cables are a bit stiff so I soldered the batt connector perpendicular to the cables to get the canopy on easily. To isolate the connections I used liquid electrical tape. I´m wondering how I could live without this stuff for so long.

And just for fun I thought I´d try a 1800mAh pack also. On my stretch Mini I can feel 30g difference in pack weight in the air, so this should be interesting. As long as I can get 4 mins out of them I´ll consider buying more.

[dr dremel]

I thought I´d be through with the weight savings on the air frame, but as I was inspecting the tail due to slight vibes on the bench I weighed the fin. I had some .8mm CF lying around (original is 1.5) and made a lighter one, even a few mm larger to keep the spinning tail farther from the ground. It may look flimsy, but it does not flex more than the original one.

[MiataJohn]

You are obsessed.

[rdlohr]

Originally Posted by MiataJohn

You are obsessed.

So true. You'd think this was his hobby or something!


Rick

[dr dremel]

lol, I once read that it´s a hobby when you put in a maximum of effort to get as little effect as possible.

Mainly I´m a bit bored. Christmas presents all bought weeks ago, work done for this year, my Gaui "X1" project waiting for parts and, most importantly, crappy weather. I have not flown for weeks.

Still hoping to get this bird in the air this year, all that is left to do is the canopy.

In this sense, Merry Christmas and Happy Holidays to everyone!
Dr

[dedados]

Originally Posted by dr dremel

lol, I once read that it´s a hobby when you put in a maximum of effort to get as little effect as possible.

Mainly I´m a bit bored. Christmas presents all bought weeks ago, work done for this year, my Gaui "X1" project waiting for parts and, most importantly, crappy weather. I have not flown for weeks.

Still hoping to get this bird in the air this year, all that is left to do is the canopy.

In this sense, Merry Christmas and Happy Holidays to everyone!
Dr

Merry christmas!

[rdlohr]

Merry Christmas my friend!
Rick

[MiataJohn]

Merry Christmas to all of the Protos people.

[dr dremel]

Well I had a few hours and finished the build.

Lightest cano I have is a blank white Fusuno, which I prepared with epoxy on neuralgic areas and put on some stickers/windows. I came to like the simple look. I´m sure there are another 10g to be saved with the cano, but it must suffice for now.

End weight with 3 battery o rings is 599g (without batt but otherwise RTF).

I´m quite chuffed about the outcome, that is 140g lighter than my stretch.

As luck would have it we also had a sunny day after the first snow, so off to the field I was and had a successful maiden flight! In fact I flew 11 packs with small pauses to warm my fingers (-5C and chilly).

The OWB I changed did work normal, no vibes to see/hear. I did catch a defect bearing in the support for the motor shaft beforehand, heli is now as smooth as it can be in flight. The tail servo mod seems to be working, tail feel was excellent from the get go. Full pitch backwards loops in the wind no problem. Except this, the wind threw me a bit off today.

Difficult to tune the heli when it´s blowing 4 Bft at times. I gave up tuning after 3 packs as the heli flew already quite good on std 450 settings. What it felt in flight was not much different from my stretch, but bogging the head comes much later. Cyclic reactions are a lot faster and feel very connected, but this is dependent on blades also . The Align 325D I tried at the field are much tamer (and were better suited for the conditions today).

I made 4 Min flights on 3S 2200, batt came down 3,83V. The 1800s I flew 3:30, 3,80V after flight, so 30sec will be added to the timer for both. The 1800 batt was very noticable in flight, downright ridiculous performance @ 760g total weight. All in all same flight times as with my stretch on 2650/2200 batts.



Can´t wait to give it a go on a calmer day!