ebay accident- Mini Protos lightweight project

[stevebaker]

Looking good there. My stock build weighs 710g RTF sans battery, but that does include a voltage sensor and bluetooth module for my Spirit FBL controller.

Having quickly scanned through this thread, I have no idea where you saved 100 grams

[dr dremel]

Hehe, thanks Steve. I guess the main savings are from the servos (around 30g), followed by wiring (15g). I googled the Spirit FBL and it is 19g minus sat, so there are another 10-15g. The rest would be small items, but it all adds up.

I was flying it again today in calm winds for 6 packs. Made a few tweaks in the FBL and it feels very nice now. I have a small wobble during tic tocs, that vanishes with higher HS, so I may experiment with head dampers. Roll rates could be faster, but I´m not maxed out in D/R yet. The 1800 packs are quickly becoming a favourite for this bird, it´s so nimble and responsive, yet I get a full 4 Mins of bashing.

BTW how is the Spirit working for you? Bailout a game changer? I could see this work for me as I seem to lose orientation during piroflip training.

[dedados]

Strange. With 1250mah pack and 890rtf weight I get 5mins smooth 3d at 2500 and 2800rpm. What HS do you run to get 4mins out of a 1800batt? BTW I am really liking your build! Good job!

[dr dremel]

Thanks dedados, I really enjoyed the build.

That´s a 1800 3S bat I´m using (159g) , I´m guessing you have 1250 6S? For now I ran it mostly @ 2650rpm, with the occasional 2200/2900, smooth 3D as well.

[dedados]

Yes mine is 6s, didn't realize you are running 3s 1800. Even though is it kind of obvious since the build is meant to be super light

[dr dremel]

Yes I think there are no smaller 6S batts available, so not ideal if one wants to save weight with packs. But the weight of the 2200 3S is not that much more than an equivalent 6S would be, so 6S is not per se off the table for a lightweight build. I briefly considered 4S with the 2100kV motor, as there are a few lighter 4S packs, but I already had the packs and the heli came with the stock motor.

[stevebaker]

Originally Posted by dr dremel

BTW how is the Spirit working for you? Bailout a game changer? I could see this work for me as I seem to lose orientation during piroflip training.

The Spirit is just amazing. It's the bailout/rescue feature and price that sets this apart from any other controller currently on the market (definitely a game changer).
I was out again today with it and I'm already pushing harder than normal, knowing I can get out of trouble with the rescue, should I lose orientation.

Set up was a breeze, it even comes with some Mini P presets, and it just flew perfect right out of the box.

We're probably at a similar level of flying, as I'm also trying to perfect piro-flips. Inverted piro circuits also sometimes catch me out.

The "X1" also had an outing today. It's still flying really nice at the moment. I haven't crashed it since finally getting it dialled in properly with those carbon blades.

[sp00fman]

You guys motivated me to cut some weight...but it's still 850g with 3s2200 pack.

Shortened all the servo wires, and soldered the motor directly on the ESC board. I will not be giving up on the Tgy306hv servos... they are heavy but just too good. I cant really see any point i could save more except using a sattelite instead of a Rx...but my Tx has no option for it.

Still, it flies well.

[Aryemis]

Haha I guess mine is porky at 964g rtf (with my lighter 216g 6S 1300, with the 250g 5S 1800 it's at 1kg).
So 750g without lipo.
I am running a pretty heavy setup though, scorpion 2520-1360, big (and heavier) lynx canopy, and stretched
Still feels very floaty on 360's, and honestly I don't want it any floatier, it already makes bigger helis feel pretty heavy.

[dr dremel]

Originally Posted by stevebaker

snip - I'm already pushing harder than normal, knowing I can get out of trouble with the rescue, should I lose orientation. -snip

That´s what I was thinking. I can do piroflips ok with the smaller helis, think I´m just too timid.

Originally Posted by sp00fman

You guys motivated me to cut some weight...but it's still 850g with 3s2200 pack.

Shortened all the servo wires, and soldered the motor directly on the ESC board. I will not be giving up on the Tgy306hv servos... they are heavy but just too good. I cant really see any point i could save more except using a sattelite instead of a Rx...but my Tx has no option for it.

Still, it flies well.

I can´t really say anything bad about the Hitecs (20 flights now), but like the Turnigy also. Maybe differences would be clearer for me with heavier blades? The SABs are superlight and you can feel it. But your @ 850g is not bad at all.

Originally Posted by Aryemis

Haha I guess mine is porky at 964g rtf (with my lighter 216g 6S 1300, with the 250g 5S 1800 it's at 1kg).
So 750g without lipo.
I am running a pretty heavy setup though, scorpion 2520-1360, big (and heavier) lynx canopy, and stretched
Still feels very floaty on 360's, and honestly I don't want it any floatier, it already makes bigger helis feel pretty heavy.

There is absolutely no "need" to make it superlight. Also with your weight increase came a significant power increase (hopefully), disk load is not everything, finding a nice balance is.

But speaking of disk load, my stretch weighs 940 with batts, and I (very roughly) calculated a disc loading of 2,2kg/qm. I got the same number for the Lightweight. If I would stretch it, it would sit at 1,8kg/qm. And for comparison: My Gaui "X1" (stretched Gaui EP 100) is at 1,3kg/qm, the mcpxs have 0,9kg/qm.

Next for the project is to make a nice design for the canopy. I played around in Photoshop and I think I found a simple but pleasing livery.


Has to wait until next year though, Happy New year freaks!

[dr dremel]

Long time since the last post, thought I could add an update.

This heli now has relatively uneventful 275 flights.

I did balance the motor shortly after the maiden due to a slight vibe, but recently noticed that I lost the balancing tape on the can. But the motor now has zero vibes (without tape) Not sure what happened here.

I finished the canopy with red 4D carbon stickers and printed the logos. Gained 2g in the process, but I like the look now. I also changed to white skids and red tail blades. Those are cheap HK blades, a little stiffer and noisier in the air, but work as good as the yellow stockers.

Although I had nothing to complain about the tail, I changed the tail pitch lever to the Lynx one. What a freaking pain to install, only after persuading the tail case with the hair dryer and brutal twisting it fit ok. I tested this on 3 tail case halves, fitment on all 3 was off like this. After that I still had to grind down the fork a bit due to lack of clearance to the tail slider. And added an epoxy stop to the pitch slider as it would still bind in certain positions. It works now smoothly as before. I did not notice any improvements in flight.

Second Lynx upgrade where v2 head dampers. Install is a bit of a hassle, they are so stiff, it´s difficult to get the FS through them. Once installed I noticed a pronounced spool up resonance. In flight - hmmmm. I´d be hard pressed to say they did make cyclic feel any more crisp. So I decided to deinstall, also not so easy as they also are pretty tight in the head block. So I´m not impressed by the Lynx parts.

I had 5 unexpected landings, 3 times with very little HS left, 2 times full throttle. Thankfully my flying location has all sorts of bushes growing hip high, so I only killed the OWB in the pinion on the last crash when I was very late on TH. No other damage to the heli at all.

Speaking of the OWB: It held up fine up to the last crash (around flight 220). I inspected the pinion and the aluminum shows very little wear. I also noticed very little belt dust around the motor. In my stretch I had sawtooth profile after around 150 flights, now it´s beginning to show wear after 250 flights. So I just hammered out the OWB per the method in post #12 and fit a known good OWB from a worn pinion.

I did inspect the heli after the crashes, but did no further maintenance except oiling the motor bearings once and regularly spraying the belt with silicone.

Not sure if I´ll stretch it again for ultra low disc load, it is fun as it´s set up now. Especially with the light 1800 batts it´s a blast at lower headspeeds. The SABs are superlight and very nimble, but a bit twitchy in fast hurricanes. I´d like to try some blades between the SAB and Align I have. Reading good stuff about Rail 326.

And finally I could persuade the GF to shoot some video of my measly flying to give you an idea how "stressed" (or not) this airframe is. This is a flight with the 3S 1800 batt, headspeed is 2340. 4 Mins like this brings the batts down to 3,79V/cell. Forgive the occasional slow camera, the bugs were really perstering us at that field.

Mini Protos Low Headspeed 3D (3 min 54 sec)

[9sec240]

Nice writeup and nice flight. Thanks for sharing!

[dr dremel]

Thanks, and you´re welcome. Although I did not have earth shattering insights to share, I just don´t like it when project threads end after the maiden flight. Because the project is never finished

[rdlohr]

Originally Posted by 9sec240

Nice writeup and nice flight. Thanks for sharing!

+1. Very cool. You gotta love this Mini P. Nice work!
Rick

[dr dremel]

Thank you Rick, in the winter it will receive even more love! I think I´ll try to vacuum form a canopy to loose a few more grams.

[Mikej]

Originally Posted by dr dremel

Thank you Rick, in the winter it will receive even more love! I think I´ll try to vacuum form a canopy to loose a few more grams.

If you do, make sure you let us know - I would be interested in one possibly ...

[dr dremel]

Sure will do. My thinking is, if I can make one, I can make ten