Fusion 50 stretch project

[flint723]

When I bought my fusion used it came with a bunch of extra parts, including a spare frame and velocity 90 boom, tt, and boom supports. And plenty of hardware to finish the airframe. So as kind of a fun side project I decided to put together a budget fusion 90 optimized for low head speed.

I had to cut the velocity 90 boom 15mm so that the torque tube was long enough; the velocity 90 must have a way different boom block or something. There is still like 50mm of clearance between the mains (695mm) and tails (116mm) so I could run longer mains if I wanted.

I installed old white tail gears, black front tt gears, black AR gear, and black main gear. I have multiples of all those gears so I thought why not try them out on this low output system.

I opted for new cyclone 695mm mains ($130) and rail 116m ($35) tails.

I picked up the electronics mostly used, but I did buy a new robird g31 ($75)
CC ice2 120a HV: $120
ds610s and a ds650: $155
Align 700mx 470kv: $85 (+new shaft and bearings: $18)
2 dsm2 sats: $30
nanotech 1450mah 6.6v LiFe: $10

I used a 12t pinion and set the CC gov to 1300, 1500, and 1700. The 6s 3300 packs from my fusion 50 are the biggest packs I have so I used them. CG is pretty close, just a bit tail heavy. I could probably fix it by replacing the all steel rudder control rod and 5 supports with a carbon rod with one support.

Maiden flight was uneventful except for an aileron wobble at 1500 and 1700 that was pretty extreme. I spend the next two flights unsuccessfully trying to dial it out with the fbl unit. On the 4th flight I replaced the hard black dampers with the softer red dampers. It made 1500 smooth but 1700 still had a bad aileron wobble. I removed the brass spacers that are under the thrust bearings and that cured the problem entirely. 5th flight I flew 8:30 min of not so smooth 3d with a fair amount of full collective stuff at 1700 and another 30 sec hovering at 1300. It was a little too much for the 3300mah packs, they sat at 3.7v/cell resting 15 min after the flight.

It was surprisingly agile at 1700, probably because of the low disk loading with the light airframe and the 3300 packs. The cyclone blades probably help a bit too, and the rail 116's held great, even at 1500. I was pretty impressed at the flight time as well, I was expecting 5-6 min with the 3300's but it looks like I could do 7:30 @ 1700 and keep the packs above 3.75 resting.

Amp draw is also pretty low, peaking at 63a and 19.8a average (vs 87.5a peak and 26.4a avg @ 2200 on my fusion 50). So my 120a esc is way oversized, I could easily get away with a 60a, and I probably will switch it if I ever get a (Protos) 700 heli that does need the 120a.

HIgh res pics:
http://imgur.com/a/wzSEe

I will try to shoot some video sometime soon.

[Michaelinpr]

Nice job. I have thought of this for a while. The only limit for me was the head and grips which wouldnt take 3d at higher headspeeds. But I am starting to like the low headspeed. That fixes the problem of too much stress on the head and tail.

How about a video. I want to hear how it sounds. I bet 1500 sounds awesome.

[markrj]

Very nice!

[SMOKEMASTER60]

Any flight reports yet In January I will ready for a new bird and was thinking to add an 800 to the fleet, but if your Fusion 90 is working well, could go that route

[garfield2412]

Very nice!
What about the weight? How heavy is your little unique Princess?

[Sowa]

I'm really digging this, good job!

[MichaelChad]

Awesome! I wondered how much work this would take. So apart from adjusting the length of the TT and boom, you were able to use V90 tail parts?

[flint723]

Originally Posted by MichaelChad

Awesome! I wondered how much work this would take. So apart from adjusting the length of the TT and boom, you were able to use V90 tail parts?

The only v90 parts I used were the boom, tt, boom supports, tail fin (had to drill one hole), and tail pushrod. And I only had to cut the boom, nothing else.

I suppose you could use the v90 tail case, that way you could have better gears and a longer fin built on.

[flint723]

Well my Fusion 90 has just been hanging up this whole time because after the last flight I noticed the tail tt gear mesh was loosening up quite a bit (original white gears). I finally got around to ordering some retro gears for it and got them installed.

I also bought the option hobby mod 1 99t helical main gear and an align 10t pinion. The option hobby gear is really nice and meshed perfectly with the align pinion. I previously had 10.75:1 gearing so this 9.9:1 ratio allows me to run 1850 rpm rather than 1750.

I took it out to the hollow by my apt where there were a lot of cottonwood leaves around. Spooled her up and I could not believe how quiet it was. Flew for a bit at 1750 then flipped it to 1850. I did a couple light pitch pumps and it seemed fine. Wagged the tail back and forth a few times and the heli started making a loud humming. I quickly landed and immediately could see there were teeth broken off the back tt gears. The tail did not let go however which was lucky for me. Afterwards I remembered there had been a leaf sucked through the tail blades at liftoff which may or may not have contributed to the failure. I'm inclined to think it did, those cottonwood leaves are pretty tough and heavy.

When I took it apart I found that one of the front umbrella gears was stripped too. I had another set of retros and installed them. Took it back out and took off from the asphalt this time. Flipped to 1850 and slowly started pushing the heli harder. Everything was fine and I really like how it feels at 1850. I did lose 30 sec of flight time with the higher head speed but I'm still happy landing at 6:30 with 3.75v/cell left in the 3300's. I could probably get close to 10 min on 5000's.

Other changes were an Edge 60a HV esc and a carbon fiber tail pushrod that eliminates the all metal pushrod and all but one of the support brackets. That 20g weight savings + moving my 3300 batts as far forward as possible has resulted in perfect CG.

I am planning to fly it a few flights tomorrow if the weather cooperates so we will see if the retro gears hold up. If I can get someone to hold my phone I will (finally) shoot a video as well.

[MichaelChad]

I did a little looking since your last post, and it looks like the v90 boom is 21mm, but the upgraded v90 n2 tail is based on a 22mm cf boom, including the upgraded tail case. I'm half tempted to buy one of the full tail assemblies and see if I can shim out the rest of the frames to match the boom block width.

I've got no issues with my first fusion using OH gears, and a 4025-550, but I just put a Savox 5065-530 (5065 = can not stator, don't know why they did that) in my other one, and I wonder how long the gear-train is going to last now.

Please keep updating! It's a fun project!





Chad

[flint723]

I managed to get a flight before and after pouring concrete today with a video on the 2nd flight. The tt gears seem fine so far anyway, although this set is noisier than the last set for some reason. I am going to order some edge 115mm tails to try out since they are narrower chord than the rail and may be easier on the tail gears. I might tack on some kbdd 112's too.

Also charged the 1450mah LiFe after 5 7min flights and put back in 873mah so that's 175mah/flight. Not too bad.

Sorry for the basically tail in only flight, I'm still too scared to try anything more on this heli.

Fusion 50 stretched to 90 low head speed (6 min 33 sec)

[MichaelChad]

Yeeaaah buddy! Looks light in the air!

Its really too bad these things are so prone to gear issues, cause they sure are awesome helis!





Chad

[flint723]

AUW with 12s 3300 batts: 4.05kg (8.95 lbs)
Without batts: 2.9kg (6.4 lbs)

For comparison my Fusion 50 without batts is 2.65kg (5.85 lbs)

[flint723]

Was going to fly the Fusion 90 today but brought the wrong balance cable for the paraboard to the strange connector on the PL6. And of course the PL6 has no option for charging without balancing. So all I got was two 2 min flights since my batts were at storage charge.

At least I got to test the Rail 105s I ordered. After my gear incident I really wanted to get away from 115 tails but did not have any 105s around. They seemed a little weak at 1500 but I couldn't get the tail to actually blow out. At 1850 it held great. I also have some Edge 105s on the way and will try them out as well.

[markrj]

That is very cool flint723!

Nice flying too.

[flint723]

I got a few flights in with the 105 tails @ 1850 and they held perfect. Gears also seem to be holding up fine. I tried Edge 105s as well and I like them better. Overall the tail hold with the Edge seems more consistent then with the Rails. I flew a little bit at 1500 too and still could not get the tail to blow out. My flight time is cut though @ 1850, down to 6:30 to end with 3.75v/cell on the 3300s.

Final configuration:
Cyclone 695s
Edge 105 se tails
700mx 470kv
CC Edge 60 hv
Ds610s and ds650 on LiFe unregulated
Robird g31
Red outrage dampers w/ thrust bearing shim removed
99t slant main gear w/ 10t pinion for 1850 rpm max governed
12s 3300 packs
6:30 flight time at 1850
AUW: 4.05kg

Latest data log:
http://imgur.com/1HMFvME

So overall I think the project is a success and I see no reason why this heli won't be as reliable as it was stock. I don't think swinging 105 tails at 8.3k rpm is any more stressful on the gears than spinning 95s at 10k. I don't much piroing stuff anyway so they should last.

I should note that the boom I had either wasn't a Velocity 90 boom or was an older style one. I think the Gaui x7 shares the same boom size as the fusion though so that could be what it was.

[Centurian]

With the current market value of the F50, I picked up a 2nd airframe. I'm LOVING my 623 bladed bird and am seriously considering streching one out to 700. Looks like the Predator boom is the cheap easy option. Got a spare beast, need to pick up servos, blades, motor & esc/bec.

With the indirect linkage eliminating servo side loading I'm thinking of going a bit cheap on cyclics.. .suggestions?

Also wondering what 700class blades are on the light side and fly well... any thoughts?

[flint723]

As far as blades go I can't help you, these cyclones are the only one's I've ever used.

Ds610's are a good value and can be picked up cheap on the forums. I haven't heard of many problems with the Ds615 either.

I have 2 sets of ds610s+ds650s that I bought used on forums. I run both on 6.6v LiFe packs unregulated with no issues.

On a side note I would not recommend a stretched Fusion as a 700 replacement, it can only be used as a low head speed 700. The tail gears will never stand up with 105mm tails at normal 700 head speeds (2k+)

[MichaelChad]

Originally Posted by Centurian

With the current market value of the F50, I picked up a 2nd airframe. I'm LOVING my 623 bladed bird and am seriously considering streching one out to 700. Looks like the Predator boom is the cheap easy option. Got a spare beast, need to pick up servos, blades, motor & esc/bec.





With the indirect linkage eliminating servo side loading I'm thinking of going a bit cheap on cyclics.. .suggestions?





Also wondering what 700class blades are on the light side and fly well... any thoughts?

Keep in mind the predator boom is 3 pieces, and waaay longer than you need. If memory serves my fusion had a 710mm boom, the gaui X7 boom is 14cm longer, and comes 2 to a pack for little more than the predator boom. Both VERY sturdy boom options!



Flint can probably comment better, but I think even he had some transmission gear issues in the beginning at least. That was the one part I could never find a better solution for.



As for servos, you can probably get away with just about anything, the ratios combined with the weight should compensate. I flew DS615s on one of mine for a while, and frankly it was hardly noticeable compared to my pimped out Fusion. I dont think you'll be able to fly it hard anyway though.




Chad

[Centurian]

I'm more of a ballerina than a break dancer, I prefer just enough head speed to get crisp response.

Been thinking about the tail gear issues, there's got to be a relatively simple affordable solution out there. I've seen what others have done with gaui & CYE stuff. The Predator box has fairly robust metal gears and they have "speed up": gears available at 14:13 ratio as well as 1:1 gears. The box itself is plastic and the tail pitch control isn't modern. Could use a combination of gears front and rear to get quite a bit of tail speed change. Some are helical but they are all fairly small diameter so not sure how much power they can handle. Just thinking out loud, I'm not very hard on a tail but the gyro system still loads and unloads the tail pretty hard all by itself.

It's a shame what has become of outrage, I really like the fusion 50 design. Wonder how much demand there is out there for solutions at this late date? I wish optionhobby would step up, I'm sure they have the resources but I understand that market size may hold them back. Sure would be cool for outrage to make a comeback...