Challenger 50% by Exclusiv Modellbau Project

[shesha]

This is thread first started originally on rcuniverse so I thought I would share the same on both forumns

Okay finally got the plane, it's the challengerII, 2.68M by Exclusiv Modellbau, the same plane that Bill Hempel built and was reviewed on http://www.flyrc.com/articles/pitts_2.shtml

The packaging is of excellent standard, the material after shipment inspection, is all in good condition, careful inspection yielded nothing but absolute perfection in the workmanship.

The kit comes with 3 plans the unten and oben plans, being the upper and lower wings, and the rudder and elevator plan is combined together.

A well documented black and white manual printed and included in the kit, comes in black and white photos of good resolution standard. The kit also includes a CD, that has the manual repreprinted in soft copy in english and german, as well as the manual being in full color. As of the manual was not clear enough, the crew at EMB has gone to the extent of photographing the entire plane in various other angles and higher quality images in their respective folder. Color manual on the cd formatted as pdf which is perfect.

I will be posting the step by step build and some notes to the build of the plane as and when I can, not as if that my contribution is going to make any difference to the manaul that is already present in the kit that covers every aspect of the build process.

I sent an email to Bill Hempel about the build of this plane and as per the magazine article that I have mentioned above, Bill says keep the plane stock and drop the fiberglass panels that come with the kit and use balsa instead to shave off a pound or two from the plane.

I also sent an email to EMB about the engine choice for the challenger, asking them about the engine class for running unlimited hover, they recommended 200 class engine and above.

Thats the collected info so far on the project.

Will start posting pictures of the build as and when possible

Please do share your insights on the project for those that have completed the model previously.

[shesha]

The stabalisers are nearly complete as can be seen from the posted pics, however I did come across a problem, the stabaliser triangular re-enforcements where not milled correctly, needed alot of shaping and adjustment at one point I thought the parts were missing, having emailed EMB they mentioned that the triangular supports are present as per the milled 5mm sheet.

I decided to make them from scratch, out of excess 5MM plywood from the milled 5MM sheet.

Here are the pics. The stabalisers need sanding and slotting, will leave all sanding once everything has been put together and ready to be assembeled on the fuselage. Will give the probond glue enough time to settle through.

[JeeUm]

Very cool, looking forward to it. Thanks for joining and bringing it here.

[shesha]

Here are the completed stabaliser's, sanded lightly, all finishing final sanding will be completed prior to complete model build up.

[shesha]

Alot of work accomplished in 6 hours worth, the elevators are partially completed, as can be seen from the photos.

Make sure that you align the elevators as per the drawings and nail them in position so when you apply the balsa strips it does not move. Also check for any flexibaility movement from the elevator on your building board so as to avoid and warping, now is the time to adjust it if any.

Just a note on completing the elevator exterior bordering, EMB does mention in the manual to soak the 2,5 balsa strips in warm water for a minimum of half an hour, at half an hour I checked the flexibility of the balsa strips. The strips were flexible but not flexible enough.

I decided to increase the temperature of the water slightly and let soak the balsa strips for an extra hour, which vastly improved the flexibility. Also note every 15 minutes do a little flexing of the balsa strips in the water, to getter better overall flexiblity.

As you can see from the pics, to create the bordering 5 strips are layed down wet and wood glue is added to the strips, with the water presence in the strips you can see that the glue is being soaked into the strips which increases the overall flexibility of the wood strips.

Alot of patience is required when bordering the corners of the elevators, I did incremental bending throughout the corner of the elevator, do not over stress the balsa strip, but apply pressure a little more from time to time.

Also note the abundance of nails I used to hold the balsa strip bordering in position, the manual pics shows little use of nails, I found that the more the nails were in place the more the balsa strip contoured the elevator base sheet perfectly.

Once in position verify the corners and balsa strips are seating correctly on the corners and add nails adequalty to seat the balsa strips snuggly, if required add some wood glue to topen seams.

I left the wood strips to dry overnight will see the results tommorrow.

On some corners I noticed that balsa strips sandwich was a bit off, so I decided to lock them in place with clips, however do not let the clips sit overnight on the balsa strips, as the wood will move as it is drying and the clips will hinder such slight movement. Just use the clips for atleast one hour or 2, then remove them prior to letting the strips sit overnight.

[shesha]

The elevators have dried up overnight and the contours have sealed in nicely, I decided to stiffen the strips with added wood glue on the elevator milled sheets. Will wait till tommorrow for it to dry up.

As you can see from the elevators, those black markings on the contours are the result of using non steel nails, which left grim and light rust, not to worry snading will take care of it, will make sure to use something better next time.

No luck today on any progress build, tail and rudder were short of pine, after searching through all the parts, those parts are definitely not in the Kit.

Missing pine strip for tail end. The pine strips have to check it out at local wood suppliers.

Anyone else was short of a pine strip?

[shesha]

Okay was lucky today, after touring half the industrial area over here, only one shop had the correct pine wood, so was able to get back to work on the model, not much though was already late in the evening by the time I got back home.

The stabs and elevator got some make over with sand paper, final sanding will be completed at the end, you can see from the pics, that the balsa strips does take form, with a little patience to let them sit overnight and the next day tack some open strips up, they sanded down very well, also not just IMHO the "probond glue" is very good at holding things together, combined with the sawdust they make good gap filling if needed.

The tail got the balsa and the pine strips, I placed the balsa strips to form the contour in the bath tub (see pics as per my previous post), but was already late at night so decided to take them out of the water and do it tommorrow instead of rushing things, especially with a kit like this one, dont want to rush things and regret it later.

Here are the pic sets, hopefully tommorrow will be able to complete the tail with the rudder.

I also visited the LHS to check out some servo's am looking at the 8411 for all surface control and running 3, 8511 on the rudder, if I am not mistaken they are all titanium based servo's, and as per the plans that came with the kit, they are clearely marked for the 8411's, which will save the time and hassle to do any servo slot milling.

Am searching for some article on the gator wing adjusters, their installation and any reviews on them prior to start working on the lower and upper wings.

[shesha]

Okay here is something to note, in the last post I mentioned about placing the balsa strips last night for 2 hours and since i did not want to rush things, I decided to skip last night and do it today, I soaked them for another 2 hours today, the balsa strips flexed even better, I think a presoak the night before and the next day is a good idea, chances of balsa breakage is less prone to happen.

Completed the tail balsa strip contour today as can be seen in the photos and the rudder balsa install is completed, left to dry tonight for tommorrow to install the balsa strip contours.

Did some rough calculations, it's official the tail group was short of pine and balsa strips, the strips work out to one meter, the overall length of the rudder is 120cm, 5 layers of 2.5 balsa strips are required to complete the rudder, with the excess of the tail balsa strip which measured out at 58 cm each, the result is short of 25cm. Will have to see if I am right about that tommorrow.

Otherwise going to have to use another balsa strip not from the kit which I really dont like to do.

Here are the pics.

[shesha]

The rudder as per my previous post was short of balsa, when looking at the pics that came with the cd for the challenger 2 build you can see that the contour is formed of 3 sections of 5 by 2.5, the top, the middle and the bottom.

I decided to have two sections of 5x2.5 to contour the rudder. Here are the pics. They will set overnight and sanded the next day.

Also took some pics of the contour sander I am using to get good clean sanding on the 5x2.5 strips. It's a dremel contour sander and if you build alot of kits, it pays for itself.

[JeeUm]

Since this is looking to be one hell of a build thread ,I'm gonna move this over to the Git R Done forum.

Gotta say, I'm blown away by the way you have to laminate and get the stab pieces to take the curves.

That take some serious woodworking skills to do correctley.

[shesha]

OKay tis been a while since I last posted, been so busy with work, got some time in to work on the first set of the lower wings here are the pics, am looking at the gator wing adjusters maybe going to order them and have them installed.

Anyways back to the pics.

[shesha]

jeeum u want me to hold till you move it or shall i finish posting and then you will move it ?

Coolnesses already shifted to the other forumn ahh like magic sorry for posting in the wrong place.

[shesha]

Well nothing spectacular since the last post, started working on the right aileron, the plastic pipe that lies within the channelised balse strip did not seat properly needed some light sanding. Whilst going through the manual, I did notice some item that was no where to be found.

The wing, rear locking tube is missing, something I have overlooked whilst doing a parts check. So several items missing as previously stated and now this item, will have to call them tommorrow and get the specs of the tube and see of I can get one milled locally.

Will post some images later next week.

[shesha]

Okay after speaking to EM in germany, turns out that the manual has not been updated, and that the black tube (carbon) "locking bolt" apprently is not what was supplied with the Kit but that of wood material, will have to do another parts check and see if corresponding wood part is in the kit.

Also noticed that the plastic sleeve that sits in the c/u channel blasa strip was supposed to pertrude on either end of the wing fins, the exact length does not match, it's short, so have to to use alternative "non original sleeve to support" the copper pipe that seats through the c/u channel balsa strip acting as the leverage point "hinge" for the ailerons.

Red Bull aerobatics team was in town today, really good airshow, though was very short.

[shesha]

I was talking to bobby from Cactus avaition today to place the order for the 3W212B4 and some other bits and pieces, and I must say that the standard of service is top notch, if bobby is reading this thanks.

Also would like to thank Bill Hempel for the previous emails on the recommendations, recent update from bill that the wing adjusters are not really that necessary if you stick with the plan build, the incidence factor would be bang on, am going to stick with his advice since he has first hand experience.

Also a note to Exclusiv Model staff, for their tremendous ongoing support via Email, top notch, even with the missing parts, they just get things done for you no question asked, thats service, even if we are half way around the world.

A great plane can only be built by by an ontourage of great service and support.

Thanks