Ultra Bandit Build

Starting a new build or conversion? Post your information, findings and pictures here.

Moderator: Dick Spreadbury

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Sat Jun 30, 2007 8:06 pm

Managed to do some more today.

Moved onto hinging the rudder. The rudder is hinged using 4 pairs of CF pins. The first job is to cut 4 slots in the LE of the rudder to allow the CF pins to move into the hinge line. Once the slot is formed you can see the other half of the hinge which is factory fitted.

Image

To make the slots neat I formed the curved ends by using my trusty dremel


Image

Once all the slots have been formed, piano wire is pass though the 4 pairs of hinges.

Image

Now 4 slots need forming in the TR of the fin. The places are marked so its just a quick job using the Dremel. This photo shows the rudder half inserted.

Note the fin is covered with bubble wrap as no matter how careful I am, I always seem to get some glue residue on my hands which you xfer onto the model.

Image

The rudder is actuated via a bar that slots in the bottom of the rudder.



Image

Here is a photo of the rudder bar installed with me holding the linkage that comes preassembled. The next job is to install this linkage and the rudder servo in the rear of the fuselage.

Image

This ia general shot of the fin and rudder , assembled to make sure everything is square while the hysol on the hinges dries.

Image

User avatar
Julian Swiestowski
Posts: 41
Joined: Tue Apr 24, 2007 12:02 pm
Location: UK

Postby Julian Swiestowski » Wed Jul 04, 2007 12:03 pm

Looks great Geoff, I like the paint job.
Corr blimey AMT(NL) Olympus HP for power ! That should push it round a bit.
Hope to see you & Bennie "let her rip" at RAF Sain Tathan later this year ?

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Wed Jul 04, 2007 9:50 pm

Hi Jules,

I am trying to get it ready for St Athan.

Geoff.

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Wed Jul 04, 2007 10:03 pm

Got to do some more today.

managed to fit the rudder servo and the linkage.
Image

The interesting point here is that for all the servos on the primary controls the instructions state to not use the servo grommets and brass eyelets. This is to ensure there is zero slop in the linkage. We can get away with this because there is zero vibration.

Oh before any of you mention it the servo is only held in with 2 screws as its a 'fitting' servo and not one that I am going to use.

I have also mounted all the control horns on the surfaces. This was all pretty standard stuff as it justs a matter of cutting a slot in the surface.

Where was I very carefull was to ensure that all the horns were equidistant from the trailing edge so in theory we should indentical movements. The photo is an example of how I measured the distance using a digital caliper.

Image

No more updates for a week or so as I am away sampling many types of beer!

Geoff.

User avatar
Paul Lewis
Posts: 20
Joined: Mon Apr 23, 2007 7:56 pm

Postby Paul Lewis » Thu Jul 12, 2007 10:42 am

Haven't you finished that Bandit yet!!!! :lol:
In the land of the blind the one eyed man is King.

Mick Burrell

Postby Mick Burrell » Mon Jul 16, 2007 10:01 pm

Hi Geoff, just been reading your thread, brings back memories.

Small tip, make double sure the nose door cam cannot fall off the side of the leg, if it does it will stop the nosewheel deploying. There is also a small screw in the front of the noseleg which can jam the door.

m

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Wed Jul 25, 2007 10:06 pm

Hi Mick,

Thanks for the heads up with the front door cam. I will double check it.

Geoff.

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Wed Jul 25, 2007 10:23 pm

Haven't had much time to spend on the UB recently so progress is a bit slow. Nevertheless here is the latest.

I have added the horns on the flaps. This is a simple job of dremelling out some slots on the leading edge of the flaps and then simpy gluing the CF horns with Hysol. Not forgetting to roughen up them first.

Image

One of my major concerns with assembling the the model is trying to keep the surface clean. I find that no matter how clean and tidy you are when you are gluing something you inevitably get dirty fingerprints on the model, or even worse, glue on surface from your fingers. To stop this I always cover the surface of the model with bubble wrap or simply masking tape. Here is an example when I glued the flap horns.

Image

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Wed Jul 25, 2007 10:54 pm

Next job on the list was to mount the wing tanks.

They come completely moulded with the pylon as part of the tank. See below.

Image

They are designed to be quickly releaseable so the front is simply a 1/4" CF rod. At the rear there is a 1/8" plywood tongue that locates in a slot in the wing. The wing is actually held on with a Quick release mechanism that work by a wire that simply goes through a hole in the bottom of a special bolt that is screwed into the wing. Hopefully of you look at the photos that will make sense!

Here is a general view of the mounting method.
Image

At the front you can see the hole for the CF rod. at the rear you can see the slot for the tongue and the 'bolt' in the middle. This photo shows the hole in the end of the bolt to allow the wire to pass through it.

Image

All three of these fixings/ holes were already partially made in the bottom of the wing, presumably using a jig. I used a dremel to open out all the holes to the correct size.

All the holes in the top of the pylon had to be made by me using pre scribed lines. Then the quick release mechnism is screwed onto a former already moulded in the pylon using two guide holes.

Image

The wire is operated by a collet and a 4-40 bolt. If you look at the previous photos you can see the 4-40 bolt projecting out of the side of the pylon.

Now this all looks very simple to do but I can assure you to get it working correctly was a real pain in the arse. The first problem was that the former in the left hand pylon has holes and slots already formed in it to locate the CF rod, tougue and quick release mechanism, which is great but unfortunately the former was off centre by about 1mm so nothing lined up. After much umming and arring I eventually decided to redrill the former for the holes and slots. This was not easy as the former is about 30mm inside the pylon and involved delicate work to ensure I didn't damage the surface of the pylon.

The right hand pylon had exactly the same problem, only this time it ws off by about 1 mm.

So now I was able to at least mount the tanks on the wings. After much messing about screwing and unscrewing the bolt I was able to get the hole at the right distance from the wing surface to enable the wire to pass through it. But I wasn't happy as it was a bit tight :x

What I found it that the wire is such a tight fit in the hole in the bolt that the amount the bolt moves in and out of the wing(ie the pitch of the thread) is too great. To put it another way if the wire is tight because the hole is out too far from the wing, then turning the bolt a half turn makes the hole not out far enough from the wing!

So in the end I just accpeted that the the quick release meachnism does work fine, its just very tight, which I guess is better than being loose. here are couple of photos of the tank mounted

Image

Image

All in all mounting these wing tanks took me 6 hours elpased time.

So onto the next job which is mounting the undercarriage in the wing.

User avatar
Dick Spreadbury
Site Admin
Posts: 166
Joined: Sun Apr 15, 2007 10:21 pm
Location: Highworth, Wiltshire

UB

Postby Dick Spreadbury » Thu Jul 26, 2007 6:53 am

Geoff,

Better to be a nice tight fit than a slack one! I suppose you could always put a 5 thou shim under the release mechanism if you felt it a bit too tight.

Cheers,

Dick

User avatar
Paul Lewis
Posts: 20
Joined: Mon Apr 23, 2007 7:56 pm

Postby Paul Lewis » Thu Jul 26, 2007 11:00 am

I thought this was supposed to be ARTF....seems to be a LOT of work! Maybe BV forgot to put the little chap in the box who does all of the work for you!!! :wink:
In the land of the blind the one eyed man is King.

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Thu Jul 26, 2007 4:57 pm

Hi Paul/Dick

Hopefully the rest of the build will be fairly routine!

Dick - Yeah if necessary I am going to experiment with shimming the release mechanismm using polyply.

Geoff.

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Sun Nov 18, 2007 7:16 pm

Thanks to the bad weather I have finally managed to get some time to carry on with the build.

The first task I tackled was to complete the tanks. The UB uses 3 kevlar tanks that come in two pieces. These have to be joined using Hysol after the surface has been keyed with 80 Grit.

Each tank has to have a vent and the receptacle for the tank fittings hysol'd in.

Image

The two main tanks are approx 12 inches long and require a baffle to be installed. This is simply sandwiched between the two halves of the tanks.

Image

Here is a general view of all three tanks completed.
Image

I haven't checked the exact capacity of all three tanks but looking at them it has to be close to 5 litres.

In addition to these three tanks I have another 2 to make which are going to be used for the smoke system.
Last edited by Geoff White on Sun Nov 18, 2007 7:51 pm, edited 1 time in total.

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Sun Nov 18, 2007 7:29 pm

Next I moved back to the fuselage and the fititng of the inlet duct, bypass and rear former.

Here is a general view of the bypass and former installed.

Image

The bypass is simply held in place at the front by fitting over the inlet duct. The bypass is also bolted to a braket that is in turn bolted to the rear wing tube former. The former came with all the holes precut and it fitted perfectly.

This method of installing the bypass is pure BVM and is very familiar to anyone who has built a BVM model.
Image

I deviated slightly from the recommended route by using 4-40 bolts to secure the bypass to this former. This is the same way that the bypass is secured on both of my super bandits but for some reason they changed these to self tappers. No idea why but why change something that works fine. You can see the bolts in this photo.

Image
Last edited by Geoff White on Sun Nov 18, 2007 7:52 pm, edited 1 time in total.

User avatar
Geoff White
Posts: 110
Joined: Thu May 03, 2007 2:59 pm
Location: Abingdon

Postby Geoff White » Sun Nov 18, 2007 7:45 pm

The final task of the day was too apply the fuselage strenghening fix that was issued by BVM after a couple of UB's crashed. One of them crashed due to some fuselage structural issue and the second one due to a alledged radio issue, although there is a fair amount of suspiscion that the fuselage also failed on this one as well.

Anyway enough of the controversy, over to the build.

The fuselage sides are joined and reinforced with 1" fibre glass tape as per normal practice, but there is obviously some doubt over the strength so to reinforce this all the fuselage seams were reinforced using a combination of carbon fibre cloth and fibre glass tape. In the photo below all the CF that is runnng for/aft in the fuse is all extra that I have installed.

Image


As per usual I made sure all the existing fuselage was keyed using 80 grit. Also it is very important to ensure that all the matting is thoroughly wetted out.

The second area of attention is the top of the fuselage just below the hatch. If you look at the photo below you can see the existing kevlar reinforcement and the new kevlar tape that I have installed as per BVM's recommendation.


Image

Here are a couple more photos.
Image
Image

There is a one more place where some reinforcement needs placing and this is right at the front of the canopy opening where the the front hook locates. As I needed to glass the fibre glass tape in with the fuselage upside down I decided to leave this to another day.


Return to “Jet Build Threads”

Who is online

Users browsing this forum: No registered users and 1 guest