My Roban 700 Apache "Longbow" build

[RCjetdude]

Finished the hollow main shaft/fixed radome mod on my Apache. Took some doing but with the expert help of my friend Darrell Sprayberry we got 'er done. He is one of the most skilled builders I have ever seen. A self taught machinist he also works with fiberglass molds and can basically make anything. The "Longbow" is something I have wanted for as long as I can remember.

[deepdiver8055]

Sweeeeeeeeeeeeet

[F106DeltaDart]

Awesome work!

[sfcfury]

Looks outstanding!!

[RCjetdude]

Been enjoying flying the Apache this weekend at the TiredIron Fall Fly-in. The new fixed Radome/hollow main shaft mod is working great. It is flying really well right now.

[F106DeltaDart]

Awesome, Looks great seeing it in the air with the radome! Curious as to what the modifications to the main gear hub were to make it work.

[RCjetdude]

Awesome, Looks great seeing it in the air with the radome! Curious as to what the modifications to the main gear hub were to make it work.

Complete re-machine of the hub to get rid of the compression slot basically.

[RCjetdude]

Wesley and Lori Miller of the Merry Boozers RC Channel shot some good video of the Apache flying at Nall in the Fall. Very nice.

[TiredIronGRB]

[RCjetdude]

Thank you George for putting that video together.

[JFandL]

Really outstanding work

[RCjetdude]

I had an issue with my main wheels turning out so I modded the main struts by cutting them just below the lowest rib and drilling them to accept a piece of 5/32" piano wire. M3 grub screws secured against flats on the pins straightened the wheels which I also changed to 2.75" Robarts. They look so much better.

[scootergenie]

Yes, they do look much better !

[RCjetdude]

This was from the TIA Fall Fly-in as well.

[JFandL]

a lot better, the UH-60 front struts do this as well. Maybe if I can find time I'll fix them.

[Alpha]

Simple but effective, I like it! I'll ask Roban to implement this tweak during the next production run. I'll be at the factory again tomorrow.

[RCjetdude]

Simple but effective, I like it! I'll ask Roban to implement this tweak during the next production run. I'll be at the factory again tomorrow.

The bolts used to secure the top of the strut and shock are M3 and should really be M4's IMHO. It would require changing the blind nuts in the fuselage and possibly some different brass sleeves but would make for a stronger solution. I don't know how they achieved the flying weight they are publishing. Mine is 22.5 lbs. and that is with 2- 8" pilot figures, 6000mA batteries and a 1.5 lb. bag of steel BB's in the nose to get it to reasonably CG. I didn't do anything crazy to the back of it to add weight. Not complaining, just raising it up the flag pole. One of the biggest helps would be to have parts available at MRC. I just ordered some parts for it from the German distributor out of necessity. The Robans are good quality Helis overall and the Apache sure gets a lot of attention.

[Alpha]

Thanks as always for your feedback! I'll discuss these items with Roban. I need to check but my old Apache didn't have 1.5lbs of BBs as I recall. Either way, it makes the case to beef up the mains an easier case to make, since the model does need some weight further forward.

Is your underslung MG functional yet? 2:1 mix with the rudder is nice for traverse. 'Haven't touched elevation/depression just yet, although in all honesty I likely never will. I'm much more interested in your radome mod!

[RCjetdude]

Hey Alpha, I have not articulated the MG or TADS at this time. Right now I am working on opening up the passageways above and behind the pilot in front of the swash plate. I also have a custom beefy aluminum hinge coming from Dustin Holloman of Raven Rock Machining to allow the horizontal stab to pivot. The fixed Radome mod is pretty slick and follows the basic design used by a gentleman named Darrell Sprayberry who built a beautiful OH-58 Kiowa with a functional pod on top of it. Mine uses a 12mm OD case hardened hollow main shaft with a 6mm brass rod inside it. The rod is fixed to the frame with a 3D printed bracket I designed. The base of the Radome has two 12mm ID x 18mm OD x 4mm thick bearings that ride on the main shaft. The head us bored through so the shaft sticks up above it about 25mm. A new main gear hub had to be machined to provide more material to secure threaded grub screws that had their ends turned down to act as pins that engage holes in the main shaft. Essentially taking the place of any Jesus bolts. A steel collar with threaded pins replaced the snap ring on the bottom of the main shaft. For the head, it uses hex head screws to clamp it to the main shaft but the thickness of the material where the Jesus bolt is located is not sufficient to hold threaded pins. The fix was to get a 3/4" ID split collar from a local Ace Hardware store and let the threaded pins secure into it. Then it was simply clamped on the head so that the pins passed through the Jesus bolt holes into the mainshaft. Attached are some pictures. Screws in the upper part of the Radome secure it to flats on the brass rod. The top of the Radome has pins that engage the base of it with the bearings. Doing this keeps everything running true.

[Alpha]

Winning as always, Steve! Honest to goodness Winning.

What printer are you using? That says a lot for the dimensional accuracy achievable with 3DP, in tandem with your design and intuition.

What range of rpm is your setup running?