BME 50 Wildhare Ultimate Build Thread
 

Greetings.

I wanted to capture some of my experiences putting together my WH Ultimate with a BME 50 in case they are of interest or use for any other Ultimate owners out there.

At the recommendation of Tom Fawcett, I'll be putting these observations in a this new thread (he pointed out that sometimes long threads can become hard to get through).

Interested parties should know that there is a very useful build thread done by Ken Bryant (with excellent contributions from a great community of fellow Ultimate owners) here: http://www.rcuniverse.com/forum/m_2965626/tm.htm

So, its off to the workshop!

RE: BME 50 Wildhare Ultimate Build Thread
 

Misc materials/electronics:
Wildhare Hardware pack (a great deal for the price)
BME 50 with Pitts muffler
Hanger 9 mounts with SWB Manufacturing standoffs for the engine
Hitec 5945s for ailerons and elevators (overkill, but I would like to buy now in case I would like to re-use for larger airframe later) wih 1- 1/4 Airwild servo arms
JR 6011 for rudder with 3" Airwild Pull-Pull servo arm
Futaba R149 PCM (using Futaba 9C)
NoBS batteries for ignition and dual HD switches and batteries for receiver/servo power

Tom was extremely helpful on the phone and talked me through various hardware choices during the ordering process to make sure I would be getting what I needed.

My Ultimate arrived in a very sturdy box (a day earlier that promised) with no shipping distress. Some minor wrinkling in the covering to iron out and we were off!

RE: BME 50 Wildhare Ultimate Build Thread
 

The engine mounting instructions in the manual work just fine for the BME - I made up a stand off block and mounted the BME to the Hanger 9 mounts and attached it to the standoff block.

This method allowed the engine to be positioned to match the spinner backplate centered on the cowl. I then removed the cowl, removed the engine and the hanger 9 mount, while leaving the standoff block in place.

Just like Tom's instructions said, the standoff block made an ideal drill guide to drill the holes for the blindnuts.

RE: BME 50 Wildhare Ultimate Build Thread
 

My standoff block was 1 7/16" but the resulting gap between the spinner backplate was too much - no worries - the Hanger 9 mount is slotted and it is an easy operation to make minor adjustments to the location of the BME by adjusting the engine bolt locations.

I used the 1" - 1 7/16" SWB Manufacturing standoffs to get the optimum positioning of the engine on the Hanger 9 mount. The standoffs come with 3 spacers and you use the ones you need.

A drop or two of epoxy (or medium CA) on the inside of the cowl around the bolt holes proved to be very useful to ensure the holes did not get enlarged during the process of installing and removing the cowl multiple times. This is important as the position of the cowl is how the location of the engine and spinner backplate is determined.

Also, be very sure that all 4 bolts are used to fix the cowl in place - the cowl is flexible and not using all four bolts can throw things off during the cowl cutting and engine mounting process.

RE: BME 50 Wildhare Ultimate Build Thread
 

Next step - wing assembly! Before gluing the top wing together, you can take some guess-work out of your servo installation later on if you drill the exit holes for your servo leads now - you can align then with the servo lead tunnels easier before you glue the wings together. The bottom wings are already drilled with appropriate holes.

RE: BME 50 Wildhare Ultimate Build Thread
 

Wing assembly delayed by having to earn the daily bread - grrr...time to apply for that full-time R/C model assemblers position...

Assembling the top wing first. Instructions are straight-forward; dry fit first, practice clamping method, dampen surfaces to be joined; spread Gorilla glue, clamp (I'm using a combination of a small ratchet strap bought at Home Depot, a larger clamp and some catalogs to keep the wing flat as the glue drys. Check the joints periodically as some gorilla glue does foam out - a quick wipe with a rag dampened in acetone takes care of this just as advertised.

RE: BME 50 Wildhare Ultimate Build Thread
 

And what aircraft assembly would be complete without expert Q/C inspection??

RE: BME 50 Wildhare Ultimate Build Thread
 

Shhhh - don't tell anyone...I got to take most of the day to pretending to be an airplane assembler! Bottom wing was straight forward repeat of the top wing - test fit, glue, and clamp in place. While it was drying I moved on to the tail feathers. The instructions are clear - especially the measure 3x and cut once. I followed the advice in Ken's Ultimate build thread and used a piece of mason's string to find the mid point of the turtle deck for my measuring device. I found that a hot exacto knife is the bomb for making quick work out of cutting super-clean openings in airplane covering (I can never find the knife with the SHARP blade...). Mark the horizontal stabilizer and remove the covering and glue in place with 30 minute epoxy - Q.E.D.

RE: BME 50 Wildhare Ultimate Build Thread
 

After the horizontal stabilizer dried, it was time for the fin. Don't tell my high school drafting teacher (Mr. Workman) that I still have his (now modified) 45 degree triangle... The slot for the fin allows some postioning - be sure to measure it and get it centered with the fuse...since the horizontal stab is already centered (from previous) you can measure from wach tip of the horizontal stab to the centerline of the fin to make sure it is centered. Pin it in place with T-pins or tape it in place.

RE: BME 50 Wildhare Ultimate Build Thread
 

Test fitting the struts and the wing tabs. One of the struts needed some minor touch-up to better fit the curve of the wing.

RE: BME 50 Wildhare Ultimate Build Thread
 

Test fitting the wing struts. Saaaaay....starting to look like an aircraft might be coming into focus.

RE: BME 50 Wildhare Ultimate Build Thread
 

I"ve got my best crew working on mine to get it done. But they always want to take a cartoon break very 10 minutes.:D

RE: BME 50 Wildhare Ultimate Build Thread
 

Kids...tooo...cute...can't...move... ;)

RE: BME 50 Wildhare Ultimate Build Thread
 

Did you decide to change engines? I see the BME with stand-offs isn't on there any more.

RE: BME 50 Wildhare Ultimate Build Thread
 

Sorry for the confusion - I took the engine off to make the fuse easier to move around and to fuel proof the firewall.

v/r

tom

RE: BME 50 Wildhare Ultimate Build Thread
 

Tom,
Are you using 4 aileron servo's or 2 and slave struts? My WH ultimate is just about done except for the aileron servo installation, I am using a 70cc FPE 4.2 on mine.
Dom

RE: BME 50 Wildhare Ultimate Build Thread
 

I would think that much power you would want 4 ailaron servos that would lesen the fluter risk.

I would like to hear how the 4.2 works though

RE: BME 50 Wildhare Ultimate Build Thread
 

Dom,

I decided to use 4 servos.

In Ken Bryant's build thread, Silversurfer has a fairly detailed discussion about slave struts and his approach to making sure that the geometries were kept even between the two sets of ailerons [ http://www.rcuniverse.com/forum/m_29..._9/key_/tm.htm Post #: 212 ] that you may wish to review....fairly comprehensive discussion that you may find helpful.

v/r

tom

RE: BME 50 Wildhare Ultimate Build Thread
 

Alright...here we are with the setting up of the cabanes and struts. I decided to go for 0/0/(-1) incidence so I could take advantage of the top wing giving me a little longer before the stall takes over. The instruction manual clearly lays out the sequence and is straight forward. I read through it several times and referred to it often throughout the sequence to make sure that I did not miss something (I guess I have learned something over the years). First, attach the landing gear and the lower wing. Next, block up the tail until the stab is at 0 degrees incidence.

RE: BME 50 Wildhare Ultimate Build Thread
 

Next, I checked the incidence on both sides of the Fuse as well as out on each wing. I was very impressed - the bottom wing set up at 0 degrees with no adjustments. I made sure to follow Tom's guidance and recheck the stab incidence regularly to make sure that nothing shifted. It was true - the lower wing set up exactly at 0 degrees - very nice.

RE: BME 50 Wildhare Ultimate Build Thread
 

Next I attached the top wing and checked the incidence - wow, it set up right at -1 degrees. After double-checking the stab and lower wing one more time to make sure nothing had shifted...yup, the top wing was spot on. Actually the center of the wing was slightly less than -1, but I figured I could make that up when I attached the cabanes.

RE: BME 50 Wildhare Ultimate Build Thread
 

The wing tabs are only set in place during this process to allow for any neccessary adjustments. Since I had a handy drill extension, I used it to drill the tabs with the wings in place. Per the instructions, I worked on the bottom tabs first. The drill extension worked great. I decided to use blind nuts on the struts (the kit is supplied with lock nuts if that is your preference)...I installed the blind nuts before doing the drilling...lesson learned - wait until after the tabs are drilled. No serious inconvienience but I had to clean out the threads of the blind nuts after the drill bit bumped into them. After drilling the tabs, I screwed in the bolts and proceeded to glue in the tabs using thick CA per the instructions. Be very careful here - it is REALLY easy to use too much and permantly glue your struts in place - I almost did it - once on the bottom wing and once on the top.

RE: BME 50 Wildhare Ultimate Build Thread
 

After doing the bottom tabs, reassemble and make sure that everything is still aligned. Then do the top tabs following the same process. The instructions recommend substituting aircraft ply for the supplied tabs - I decided to use the stock tabs, but I reinforced the tabs with CA. Again, make sure that everything is dry before sliding those struts on (ask me how I know [X(] ). Next on to the cabanes. Dry fit. As per the instructions, I had to grind off some from the front and rear vertical cabanes. No big deal - grind, check, grind and you are good to go. Again, double check everything with the incidence meter and then grab the drill and let fly! Next, on to the hinges.

RE: BME 50 Wildhare Ultimate Build Thread
 

Based on a couple of lessons learned from Ken Bryant's build thread, after I took the bottom wing off, I reinforced the former in front of the bottom wing hold-down bolts with some triangle stock and also used some balsa to build up the area over the wing hold down blind nuts.

RE: BME 50 Wildhare Ultimate Build Thread
 

I used Gorilla Glue for the hinges. I tried the technique of using the masking tape to keep the foaming glue off the wing, but it seemed to me to take as much effort as watching the hinges closely and cleaning up the excess as it appeared. Per the instructions, I glued the hinge points into the airframe first.

RE: BME 50 Wildhare Ultimate Build Thread
 

While those were drying, I spent some time measuring and drilling the rudder and elevators for the control horn. A post on Ken Bryant's thread indicated that doing it before attaching them was more convienient. Having bought the hardware kit from Tom, everything was right there - usually I end up having to run to the hardware store for some widget that I overlooked! Next - attaching the control surfaces to the airframe

RE: BME 50 Wildhare Ultimate Build Thread
 

Grrrr...spend more time measuring and less time stylin for the camera! I drilled one of the stab control horn screws ~ 1/8" too far back. Found a spare hard wood dowel and with some thick CA and a razor knife I fixed it up. This time I measured it twice and used the drill press! I'll put a small patch of covering on the top when I get around to it - the control horn support covers the bottom of the fix just fine.

RE: BME 50 Wildhare Ultimate Build Thread
 

I installed all the control surfaces. A paper towel dampened with acetone works great for removing any Gorilla Glue that oozes out. I installed the tail assembly support wires. The instruction manual says to drill holes, but if you look carefully at the tail section, you'll find predrilled holes under the covering (use the manual pictures as a guide). I like the mounting system. I mis-placed two of my attachment tabs, so I made a couple out of some metal I cut out of a radiator hose clamp that I had laying around. Two of the clevises had to be replaced as the threads were out of tolerance and would not engage the adjustable portion - no biggee: the spare parts box had a couple of old clevises that did the trick. While I was here, I also installed the tail wheel

RE: BME 50 Wildhare Ultimate Build Thread
 

Now, off to the races...errr, servos...

RE: BME 50 Wildhare Ultimate Build Thread
 

Duplicate entry

RE: BME 50 Wildhare Ultimate Build Thread
 

Pat,

May I engage you in a dialog in this thread regarding servo geometry and y-cables vs. JR matchboxes?

If you'd rather do via PM, please advise.

v/r

tom

RE: BME 50 Wildhare Ultimate Build Thread
 

Tom,

I'm already married so an engagement will be out of the question;) What would you like to cover in this area?

My opinion of Wye harnesses is pretty low. They work well for providing power to separate end points, but do nothing for matching travels and centers. Ifd you cannot mechanically make a given number of servos the same with a Wye, then it's not going to happen. Too much room for error and mis-match with Wyes.

OTH, although a Matchbox will without a doubt cost more, the level of accuracy and ease of adjustment is hard to beat. The linkages and center points still need to be as close as possible, but hitting all the centers and end points for a given number of servos is pretty much assured. On a two servo per wing side installation, two Matchboxes would be needed. The power draw is not that big of a deal.

Another up side of using Matchboxes is that they provide an easy method of providing a separate power supply to the servos they control should that be desired. If you were ganging 2 or more servos and wanted to assure that you never drew down the receiver supply, then a Matchbox makes that pretty easy.

As far as the actual geometry of the linkage installation, that remains pretty much the same as in any other installation. A one to one ratio between the servo and the surface horn, preferably with a greater ratio at the servo and a lower ratio at the surface horn. Minimizing the length of the servo arm reduces wear at the servo gears, so if you can obtain the travels you desire with a one inch servo arm and a shorter length control horn connection, from the horn to the center of the surface pivot point, all would be as good as it could be.

The above is pretty much the way I always go and have only had issues with servo wear when longer servo arms have been used. That 1-1/4" stuff is pretty hard on the gear trains. That's one of the reasons that the JR 8611 servos have developed a name for faster gear wear than other servos. They're getting leveraged pretty hard with the longer arms.

If there is any more you want to discuss, let me know and I'll see what kind of mischief I can stir up;)

Pat

RE: BME 50 Wildhare Ultimate Build Thread
 

Pat,

Hopefully the sand hasn't gotten into too much over there... I'll try and get over being turned down :)

My set-up was originally going to be matchboxes with individual leads (4 aileron servos on a one match box and 2 elevator servos on the other). The electronics are to be powered via redundant batteries & switches through the receiver. After reading several threads regarding servo set ups, I would like to double check my understanding...your notes have already helped quite a bit - thank you.

There is a very comprehensive article here on RCU ( http://www.rcuniverse.com/magazine/a...article_id=486 ) that talks to the importance of setting up the geometry of all the linkages so that the travel is as equally matched as possible. I think that I understand that. However, both that article (and a set-up video on the DoD website) talk to the usefulness of the Hitec servo programmer in matching all the servos. It seems to me that if the servo - control arm linkages can be made as identical as possible, then the matchbox will provide the remainder. Any thoughts on advantages of using a programmer in the place of matchboxes?

v/r

tom

RE: BME 50 Wildhare Ultimate Build Thread
 

Tom,

This is a personal viewpoint of mine only, so take it from there. Although the Hitec line of products work well for many people, I lost faith in their stuff a couple of years ago and therefore pay absolutely no attention to their claims and advertisements. It cost me waaay too much the lst time. I'll tell ya the tale someday, but not on any part of RCU.

If you are happy with the product and they work well for you then that's the way to go. From my perspective, it's a lot easier and cheaper to go with a Matchbox when I need it, rather than have the need to program each and every new servo when they come out of the box. It won't take much searching to encounter a few people that have improperly programmed a servo and trashed a plane.

RE: BME 50 Wildhare Ultimate Build Thread
 

Pat,

Thank you very much for sharing. I think the best part about RCU is being able to consider other points of view and still having the freedom to go off and foul up anyway :D I've got the matchboxes and I think that is the way I am going (I think I am constucting the world's slowest moving build thread). Another question, if I may? The screw-type horns (Du-Bro, Rocket City etc) offer a lot of adjustment. Are there inefficiencies introduced if there is too much of an vertical angle from the plane of the servo arm to the linkage?

v/r

tom

RE: BME 50 Wildhare Ultimate Build Thread
 

I personally think that the screw type of horns offer the most accurate and widest range of adjustment out there at the moment. The other options are to use something that you would have to drill holes in and pray that you were perfectly matched with the hole locations. That's not likely for most people. As a rule, there is very little slop in this type of linkage installation if the hardware is correct and of high quality, and a higher end servo is used. With lower end servos and everyday linkage, a lot of slop can be easily built in no matter what you do with the adjustments.

As far as shaft accuracy is concerned in the vertical axis of the screw shafts, the closer they are to a true and matched in alignment with the surface, the better. However, as we've all seen there are often differences in the angles of the holes drilled for the shafts. When those differences are more than just a little bit, I like to fill the pre-drilled hole with a wood dowell and drill new holes. I've had this type of stuff occur on just about every plane I've ever built that had hard points. Worse, I've done it to myself with a couple of planes that I scratch built. It's never a big deal to fix.

The Matchboxes will permit a lot of freedom in the alignment of those screw shafts. That's another reason I like them. BTW, a slow build is usually one where the builder paid plenty of attention to diong things right. So far it's looks like you've been following that track quite well. Keep up the good work.

Pat

RE: BME 50 Wildhare Ultimate Build Thread
 

Pat,

Thanks again. I've hinged my ailerons to the wings so I'll be drilling the hard points while the control surfaces are on the wings. I'll plan to clamp the control surfaces & wings so they don't shift around. The drill point will be a combination of where the servo arm lays out combined with the screw horn length to make sure I get the pivot point on the hinge line. Any tips regarding drilling the vertical axis of the control horn shaft accurately?

tom

RE: BME 50 Wildhare Ultimate Build Thread
 

Yep.

If you lay another piece of aileron stock over the one you want to drill, opposing the angle of the one to drill, creating a "square" surface, you can obtain a pretty accurate hole even if you drill it free hand. If you have a drill press or some of the Higley drill guides it gets even more accurate.

I'll be out of touch with the free world and the internet for the next 30 days or so. Have to go to one of those "special" places for a bit.

Pat

RE: BME 50 Wildhare Ultimate Build Thread
 

Pat,

Perfect tip - thank you. God speed.

v/r

tom

RE: BME 50 Wildhare Ultimate Build Thread
 

Hi Tom,

I finished up my Ultimate/BME 50 late last fall, just in time for the snow....
The good news, I have flown mine a few times now but have been having trouble with the carb going wacky in flight.
My Stinger G-62 combo did the same thing a few years ago. I think we have all heard about this happening before.
I would be interested in hearing about how yours runs when you get it flying. If you or anyone else is interested in how I solved my problem, I can post some pics...

Good Luck with it, Greg.