Wow, it flies! -- Zoom/Shogun/Dolphin

[Sar]

I was worried I was getting into another hummingbird situation, but I flew the Shogun today just a little bit and was really surprised with the responsivness and stability. It still flies like a micro, but much more stable than the HB ever could hope to be.

I installed the GY401 and spun it up, the tail was all wagging all over the place, so I turned the gain down without much result. Then I remembered I had turned the headspeed down for some testing, once I fixed the throttle curve the tail locked right in.

Also learned you shouldn't land the zoom in grass. My first attempt stripped the carbon tail drive shaft "hex" shaped front end. I had to CA the frontmost tail drive gear onto the shaft. The second flight attempt was done in my buddies hangar and it worked great.

[Hotshot Charlie]

Hi Sar,

I have been interested in a Zoom. Keep me informed of your likes and dislikes as you play with it.

[Sar]

Hey Hotshot, here's what I have so far

Likes:
Very easy to set up, it's ARF so just a matter of adding servo's and power system.
Very portable
Sounds cool with a brushless
Looks good :)
People are making tons of upgrades and mods for it.
No nitro mess

Dislikes:

Tail drive system could have been built a little better, I'm not big on how the gears are attached to this carbon drive shaft. The front of the tail drive shaft is machined down to about 1/2 the driveshafts width, and then the gear is slid over this, it could have just as easily been left the same width, and a bigger hole drilled through the gear. However it's not a major problem if you have some CA around.
Excessive use of Z bends in all of the linkages.
Swashplate could benefit from four screws in the empty holes on the bottom side to hold the bearing securely, again easily fixed.
No nitro mess

[Sar]

Photos

[WillJames]

Great photos!! Thanks for sharing Sar!! :)

[Hotshot Charlie]

Hey Sar,

Thanks a bunch !!! Have you tried it outside yet? Wonder how it handles a little breeze? The little Century Hummingbird doesn't like ANY wind.... hehehee, but it is less than 1/2 the price !

[Sar]

I was going to fly it outside yesterday but the American flag at the airport was standing straight out trying to pull itself off of the cables, so I abandoned that idea. My buddy let me fly it in his hangar next to a $1Mil King Air instead, which made it seem like a very very tiny, and cheap heli). I know the FP hummingbird was lousy in the wind, but Century's site says the collective pitch one is OK.

[WillJames]

That video from Chattanooga showing Harlan flying his Zoom was in about 10 to 15 MPH winds. Seemed to handle it fine.

[Hotshot Charlie]

Hey Will, is that video still on line?

[WillJames]

http://www.helifreak.com/viewtopic.php?t=1375&highlight=chattanooga+video

Yea Baby!! :D

I did a search for Chattanooga AND video

Harlan flys the heck out of that Zoom in the video. Watching it bring back fond and fun memories of Chatt. I'll be going back next year!! :)

[WillJames]

Actually when I look at the Harlan video, it was filmed early in the day so there wad not much wind then. :oops:

I have also seen Henry and Rob fly Rob's Zoom in some pretty good wind at Clintstones back yard at one of the Heli Invasions. Seemsd to do good for its small size.

[Hotshot Charlie]

Hey Will,

Thanks, downloading right now !!!!

[Hotshot Charlie]

That is a Hot little heli.

Cool and the pilot did a great job flying it !

Hmmmmm....... Zoom 400.......

[WillJames]

Be sure to talk to Rob first (BimmerM3) he has experienced some trouble, so a reality check before purchase may be in order. Can't remember exactly what problem he is having, but I know he is a little frustrated with it right now. Never hurts to talk to people who have been living with one for a few months.

[Sar]

I'd like that info too :P I was all over the place looking for bad info, aside from the need for a few mods I couldn't find anything fatal. If there is a fatal flaw or something, I'd love to hear it before I spend MORE... Time to send a PM.

[WillJames]

Your info about the drive shaft was interesting to Sar.

[rob_jones]

Hey guys! Well, I finally got two flights in a row without any failures! I finally feel like I have the Zoom really dialed in now. I flew it in about a 10-15MPH breeze yesterday afternoon and it didn't seem to bother it too much. It gets tossed around a bit in a hover, but in flight it's a lot better. I did some flips and loops and it's a little slow, but very entertaining! With a Himaxx 2025-4200 and 9T pinion with a 3-cell LiPloy is has about the power of a hot 30 glow heli. It climbs with real authority and tracks very well in forward flight. The cyclics are a little slow, but I'm trying to figure out a way to get rid of the weights on the flybar paddles. If I can do that, it ought to liven things up.

Now for the bad news: The problem I have been having all along is with the lousy (weak) design for the tail rotor drive. As Sar has discovered, the machined hex on the drive shaft is a weak point. So are the gears. The input gear on the front of the shaft is especially sorry. The output gear at the aft end is a little tougher, but not by much. I have lost count of how many input gears I have stripped. I think the problem was mostly incorrect mesh settings. Once I got it right (by trial and error), they held up much better. Using a brushless motor also probably hastens their demise. And if you even THINK about touching a tail blade on the ground (or grass) when it's spooled up, you can just go ahead and plan to replace the input gear. I have learned one trick that helps and thought of another to try. The first is to always land in throttle hold. I'll get into a low hover (maybe a foot high) and hit HOLD and set it down in a mini autorotation (haven't had the nerve to try a full auto yet - not much intertia in those teeny blades). That will save the tail gears from any extra stress and seems to work. Take off must be quick. Once I get the head up to speed I lift off quickly. If your tail blades are stained green on the ends (like mine), you can expect to be replacing input gears. The second idea is to make a landing pad out of a piece of plywood and some carpet. That will give a firm and flat surface that is grippy. I should have it made by the next time I go flying. Incidentally, on the "last" flight yesterday I touched down a little harder than expected and guess what? Stripped input gear. It was the last one that I had on hand, so I need to order more.

I have impoved the drive shaft to prevent the machined hex from failing. At the SEFF event last weekend I found some hollow carbon rod that is close to the right size. It's a slightly larger outer diameter than the 3mm the Zoom uses so I had to sand it down. I had an extra tail shaft (the brass hex that actual tail rotor is attached to) and cut off a 1cm piece. I epoxied that into one end of the hollow rod and epoxied the tail pinion to the other end. This is a much stronger way to do it and I can easily make more if I break it. The new metal hex won't strip and the rod is straighter than the original. I noticed a big reduction in vibration with the new shaft. I think I have the card for the guy I got the rod from. If I can find it, I'll put anybody interested in touch with him. FWIW: I spent several hours online prior to SEFF trying to find this stuff. I couldn't find it anywhere! If anybody knows where it can be bought, please let me know. Ideally, 3mm hollow rod would be better so you don't have to sand it.

This thread on Ezone:

http://www.rcgroups.com/forums/showthread.php?t=238657

discusses a possible mod using a belt drive for the tail. It looks very promising and is just what the Zoom needs. It's still being developed, but I've already asked to buy a kit when he gets it ready.

This is my overall impression of the Zoom/Shogun/Dolphin/Zap 400 (I think I got them all :mrgreen: )

The Good: A "real" helicopter, held together with screws (not CA and double-sided tape). Excellent flight characteristics and handles wind just fine. Great looks and performance. The only one of its kind - at least for now...

The Bad: Plain sorry tail drive system. Must be very deliberate when setting it up. Will not tolerate any abuse (touching the ground when powered). Fairly costly. I have about $500 in mine with a brushless motor, ESC, servos, LiPoly, GY-401. Parts cost about the same as a 30 ($10 main shaft, $15 tail boom, $6 spindle, etc)

The Bottom Line: Not inexpensive, but definately costs less than what it would take to get a Hornet or Eolo to this level. A very cool 3D-capable helicopter that can be flown just about anywhere. But I wouldn't try it in my living room. The 2200 RPM head speed is very intimidating in a small area. To make it more durable, some mods are going to be required, but once you get it dialed in and learn the proper care and feeding, it can deliver lots of fun!

[WillJames]

OK Sold. I will be ordering one from Mac Hodges. Thanks for the info!!

I am also interested in the belt driven tail. Thanks for the link. EZone is killer!!

Thanks again for the great info Rob and taking the time to get it all down!

[rob_jones]

FWIW: I talked to Mac the week before SEFF and the Zoom version of this airframe isn't going to be officially coming to the US. We get the Shogun which is identical except for the decals. He has, I think, 6 Shoguns ordered and expects to have them in time for the Heli Invasion July 16-18. You are coming to the invasion, aren't you? Bring money so you can take your Shogun home with you! :glasses2:

Thanks again for the great info Rob and taking the time to get it all down!

Not a problem :mrgreen: Just trying to do my portion...

[Hotshot Charlie]

Rob, this is the other Rob (alias:hotshot charlie),

Thanks for all the great info. It is much appreciated.

Hey Will, what kind of price does Mac have on the Shogun?

Thanks gentlemen !!!

[Tabbytabb]

Heliproz has the shogun for 189.00!!! get em while their hot :)

Tabb

[Sar]

Hey _Rob, you might want to try www.nyblimp.com for finding the right diameter carbon tube. I bought some stuff from this guy a while ago and the prices were pretty OK with decent quality priced in 36" lengths.

[rob_jones]

Thanks, Sar! I will check them out.

[TORNADOREX]

Where did you order your gears from? lhs? or ?? I need some to even get a first flight. :arggg:

[Sar]

http://www.hobbypeople.net/part/16310001.asp

There's two pages, click the arrow at the bottom of the page for more parts.