lesliehowell

Here is my list of complaints on the Hanger9 B-25J. I also just built and flew the new Piper Pawnee from Hanger9 and it is really nice. Any fears about the landign gear mounts are totally unfounded as my first flight had an engine failure at 50' at the end of the runway. I put it in the tall grass and it did no damage at all.

So here is what I had found wrong. I worked around all of it and if anybody is interested in them let me know.

Hanger 9 B-25J Construction Problems

Listed below are just some of the problems that I encountered while building the Hanger 9 B-25J. Listed below are the pages and the construction numbers.

Section 4: Operation Flap Linkage Installation.
Things went well until step 12 and 13 when it called for the linkage installation. I found that the linkage provided to me did not allow for the use of a “Y� harness. I tried every variation that I could think of thinking that the instructions lagged behind the actual kit. But this didn’t stop me from just using radio mixing to solve the problem. After the initial installation I found that the plastic links provided were of the wrong thread and easily slipped off the end of the threaded rods. I used some Robart plastic links and solved the problem.

Section 6: Glow Engine Installation.
This section went as instructed with the exception of the cowling cut out. And this is just a personal preference. I cut the cowling out to give me access to the fuel and vent lines. After running these engines (EVO 36’s) I found that the starboard engine would lock up before it reached the top of the stroke. Thinking that running this engine would allow it to seat but after five tanks of fuel it still has the same problem. Now I think there just may be a more serious problem right from production. Since this is my first and last experience with these engines I wish Hanger 9 had the foresight to provide for a four stroke installation. Horizon Hobbies is the distributer for Hanger 9 and Saito so what is deal? There was not even a mention of a four stroke and I find this kind of strange. Is the real reason that they wanted their customers to go the electric route? If they had done that I certainly would not have purchased the aircraft at all and saved me a lot of money and grief.

Step 5, the instructions call for what had become the standard Robart nose gear steering set up using the pull-pull cables crimped close to two ball links. But in the kit Hanger 9 furnished a different set up using nylon clips and threaded rods. I believe this to be a better option but should have been in the instructions to avoid surprises and this set up should become Robart’s new standard set up.

Step 7, nose gear retract installation, was interrupted when I discovered that there was no way to install the “T� nuts to the bottom side of the mounting rails as these rails are too close together for a finger to access the bottom of the rails. To resolve this problem I cut out an access hatch in the nose green house area. My logic was that since there already was one hatch for the battery one more hatch wouldn’t hurt anything. I do wonder if it will degrade the integrity of that bulkhead. But very little strength is required for this design since the stress levels are at a minimum.

Step 21 mounting the retract gear into the nacelle’s, The instructions call for drilling four holes in each nacelle for the 4-40 mounting bolts but the Robart main gear was bored out for a 6-32 bolt installation. This would allow for way too much slop in the gear. Also the gear had way too much movement in every direction to allow for an accurate installation. There are no instructions as to where the gear was to be mounted fore and aft. This really leaves you in the dark because if it is mounted too far forward you run the risk of having an airplane that won’t sit on the main gear but rather tip back on it’s tail. If you mount it too far to the rear you will have an aircraft that needs more nose weight for balance and one that is a lot harder to rotate into a take off position.

Section 9, Retract Valve and Hardware.
Come on now, how hard would it have been to furnish a couple of laser cut pieces for this set up or at least full size parts printed in the book. I didn’t have a problem doing this because of the number of models I have built using the Robart retracts. But a first time builder putting retracts in an aircraft don’t realize the problems that you can encounter. And it should be more specific as to where the Robart retract valve should be installed to clear the wing as I had to move it more than once.

Section 10, Engine Nacelle Installation.
The first problem I encountered was that the dowels installed in the wings did not line up with the provided holes in the nacelles. They were off by almost one quarter inch. And the holes were too low in reference to the wing shape. This meant that the nacelles would not go all the way down to the wing and seat there. I solved the problem by using a quarter inch round file and carefully filling each hole in the nacelles until they just fit. Then there was the rear mounting holes which did not line up at all with the “T� nuts in the nacelles. These too were off by the same amount. I had no choice but to re-drill the holes to match the nuts in the nacelle. Since I had chose the retract installation I had a clear view of the bottom side of the wing in that area.

Section 11: Wing Installation.
Here too I found a line up problem with the “T� nuts that were preinstalled in the fuselage. I just re-drilled the holes to match the “T� nuts location then I installed the plywood plate.

Section 12: Rudder Servo Installation.
Step 7, this is where I found major problems that even had an experienced builder with problems. The first thing that I noticed when I did a dry fit for the rudder to the horizontal stabilizer was there was way too much slop in the fore and aft movement with the rudder, also it was too rocky left and right. It was just really an unsettling feeling to get this far along and now I have to find some reference points on the fuselage to align the rudder to the horizontal stabilizer. A solution at the factory would be to laser cut the horizontal rib shape into the rudder and make it bottom out to produce a perfect alignment. The way I did it was to mount the horizontal stabilizer to fuselage and take measurements along the fuselage to get a center line for reference. Now by measuring from the centerline to the front and the rear of the vertical stabilizers I could get a straight setting. Then I repeated it on the other side. It still left a gap at both ends of the vertical stabilizer to now do something with. I chose to fill the area and cover it with matching heat shrink material that I had ordered from Horizon Hobbies. I would have done this anyway to have patching material for hanger damage, but a lot of new modelers would not have done that.

Section 12: Rudder Servo Installation.
Step 17, this is another area that I encountered problems and it was with the location of the pre-drilled holes in the elevator halves. If I just did what the instructions told me to do I would have had a 3/8� gap on one side and a 1/8� gap on the other. I re-drilled the one half to make both sides come out the same.


Problems encountered after building:
Now that I have had time after building the model I have run into more serious problems. While running the starboard engine for the recommended break-in I noticed it rotating at the spinner like the engine had some mounting bolts come loose. So off comes the cowlings again, and another inspection. I grabbed the engine by the spinner and tried to move it back and forth. I noticed that the nacelle was so poorly manufactured that the firewall on the nacelle flexed in every direction. Since this came pre-assembled with the engines installed there is no way to access the back of the firewall to re-enforce it from the back side. Another problem in trying to solve this manufacturing mistake was the nacelles are made from what I believe to be FRP (fiberglass reinforced plastic) I am not exactly sure as to what step to take next. I have a lot of time and money already invested in this model and now to have to do this! I will be sure to use a different manufacture in the future. And you will have to remember, I have yet to be able to take this aircraft for it’s maiden flight!

Solution to the poorly manufactured nacelle’s:
Well, I decided to remove the paint on the firewall and further inspect for a solution to the flexing problem. I finally decided to brace the firewall with a piece of 1/8� light plywood. I used Gorilla glue to bond the two together since it will bond all types of plastic to just about anything else. Next was the cleanup and repainting of the firewall after a thinned out coat of epoxy was applied to the bare wood. Now for the next problem I encountered. While I was masking off the firewall I noticed that the bottom of the nacelle was extremely soft like the plastic had been stretched too much during the molding process and was now extremely thin.

With the amount of time involved at this point and still more problems I am about to strip the aircraft of all the hardware and trash the model.


Conclusion of advanced repair problems:
This is not what I have come to expect from an ARF model airplane. And after several emails to Horizon Hobbies they not once offered to replace any of the bad parts in any way shape or form. Had I purchased a new mixer or a vacuum cleaner from a department store and did the same thing. I already would have had a replacement or an offer to refund my money. In this case I would rather have a refund as I have no confidence in the manufacture being able to replace this product with a good one. Is this what we the purchasing community of hobby supplies have come to expect? Being taken for our hard earned money with no recourse except not buy from them anymore.

Sincerely yours,
Leslie H. Howell
635 Yale Court
Des Plaines, IL 60016-2332
847-296-2275
[email protected]

rc74

My Feedback: (6)

Here is a pic of six B25 for are annual Flying Circus. Left to right, first is a Top flight, 3 H-9, a KMP, and then another H-9. Check out more at www.gcrcc.net

raveon

can anyone tell me how i can get round this problem ive got i want to install two sc52 four strokes in my hangar 9 b25 mitchell but when i try and fit them the prop driver sticks out much to far ive got os40fxs in at the moment and i find them under powered and not reliable this is my second b25 first one crashed when i lost a engine at low altitude would be grateful for any advice or input many thanks Ray

lesliehowell

Raviun,

I installed two Saito 56's in a friend of mines and they fit, but I had to make a small light plywood tray for the throttle arm to clear. It was very easy to do and it has tremdous power. I seen one at a local field flying with two Saito 40's in it with 11 X 5 two blade props on it and it appeared to fly alright. Well anyway he was happy with it, but of course he is an old fart like me.

Sincerely yours,
Les

modawg73

Ray,
I mounted two saito 62s and had the same problem. My workaround was to mount the cowlings further forward. I used a 1/2" square hardwood stock and cut off 8 pieces about 3/4" long. Then I epoxied them onto the front of the firewall. Then i marked the positions of these blocks with tape and cardboard, set the cowlings where i wanted, and drilled using the cardboard templates as a guide. I used the included mounts for the engines, but had to move the engines forward on the mounts to have clearance for the carb and throttle arm. All in all it turned out pretty well. The hardest part for me was lining up the cowling and holding it in place long enough to drill the holes. I used the dummy radial to hold the cowling in place. I don't think I can leave them on because I can't get the cowling on over the rocker arm covers with the dummy radial in place. I'll try to get pix on if you wouldnlike of my final setup.

Good luck.

Ken

lesliehowell

Shoot Ray,

I had to do that with mine anyway because there was nothing to screw to at the recomeded locations, just hollow behind them. They have been the standby for cowling mounting for many years and I think still the best method.

Les

blemoine30

i put two thunder tiger 75 s in mine and did not have to modify any thing ,because of there phyical size, turn a they turn a graupner 3 blad prop about 9200 rpm 11 7 prop

raveon

Dear Ken would love to see pictures of final set up of your engines and cowls thanks very much for your feedback regards Ray

mobyal

Don't know if anyone's looking for one of these it's been on backorder from Horizon since last Fall but I was in Hobby Hanger in Chantilly VA yesterday morning and they have two for sale, one NIB and one completely built. Their phone number is 703/631-8820.
Al

modawg73

Ray,

Was hoping to get them done this weekend, but had a snafu with the mufflers. Here are pictures of the mounting of the engines. I'm out of town, but hope to finish the bird by the end of the week. Cowls look good on it, the spacing is about a gap of 1/2" between the shortest part of the cowl (where the nacelle scoop is) and the firewall. the short blocks of wood in the picture are for mounting the cowling. The longer blocks do double duty. They mount the cowl and also are used to secure the flex pipe muffler.

FYI, as shown in the first picture, the small block on the top (it is actually the bottom since the plane was turned upside down) doesn't align properly. I am going to have to cut it off and re-align. If you notice that the original mounting points on the nacelle firewall stick out about 1/8", so I aligned them all with the outer edge of the firewall and they turned out perfect. The top/(bottom) one i mounted even with the edge of the firewall, but didn't take into account that it wasn't sticking out like the other mounting points. The only reason I didn't use the original mounting point on that firewall is because I need to strap down my flex pipe, and I couldn't secure a long enough piece because of the cutout for the muffler in the nacelle.

If you need more pix quickly, I can try to get them by Wednesday, but it will probably be the weekend before I get it all done.

Ken

modawg73

COG help please!

I was trying to get her ready to maiden this weekend, but had an unexpected thing happen with the center of gravity. I put her on a great planes balancer at 3 3/4" like specified, and she was significantly nose heavy. I had to add 5 1/2 oz. of lead to the tail to get her to balance. Since I had a temporary setup (i didn't have the final mufflers, so was using the factory muffler for the saito 62s) i didn't feel like adding the lead until I was at the final setup.

A couple of quick questions that I would love your perspectives on.

First, I balanced her with retracts in the up position and with gas tanks empty. Is this the best way to do it? (first model with retracts that fold front to back) The manual doesn't specify whether to do it with the retracts up or down.

Second, i have 2 5-cell AA packs in the nose. Has anyone mounted the batteries anywhere else. I am thinking of moving the packs back to the wing center section. I am thinking it is best to balance without adding weight if you can.

Third, I am of the opinion that a COG too far forward is a livable situation, but too far back makes for hairy flights. How far would I have to go in front of the specified COG before I would be in trouble? Is it possible to have it too far forward to be flyable?

Thanks for any help you might be able to provide.

Ken

da Rock

Yes, you balance with the wheels up and tanks empty.

Move the packs as far back as needed. Use heavy wire extensions. You're absolutely correct about dead weight.

Find out where the CG range goes. Best way to do that is to measure the model, plug the measurements into the application listed, and run the application a couple of times. Using 5% margin will tell you how far back the CG can go, and 20% will tell you how far forward. The CG location affects the elevator sensitivity. If you choose to move the CG forward of the mfg's suggested, then rig your elevator to have more throw than the mfg's suggested throw. If you move the CG aft, then rig the elevator to have less throw. As long as the CG is in the range the airplane should fly reasonably well. But in your case, moving the batteries back will help quite a bit. Using geistware will reliably predict what can be done to help also.
http://www.geistware.com/rcmodeling/cg_super_calc.htm

modawg73

Rock,

thanks so much for the help! much appreciated

Ken

modawg73

Ray,

Here are the shots of the cowlings. I still have two small holes to drill, one for the needle valve, and one for the fueling T.

Other than that, the cowls are done.

Ken

BigGuyJT

Just jumped on this thread. Looks good there modawg73. Where did you get your flight crew?

modawg73

BigguyJT,

Welcome. I got my busts from century jet in Kentucky. They are the WWII busts. I think they were about $30 apiece. I had to cut the nose gunner down a bit to get him to fit.

Ken

raveon

dear ken thanks for the latest pictures of your cowlings they were very useful now i see how you fitted four stroke engines in the cowlings you moved them forward kind regards Ray ps let me know how the test flight goes

BigGuyJT

Thanks Ken. I'll check 'em out!

show871

I have evo .36's, and a full robart air retact system. Could I please get some suggestions on "about" where my 5.5 oz rx battery should be to get things to balance.......I was just hoping to be close and tweak it from there. Thanks 871

jbarnes

Plane is tail heavy so you need the battery up front under the cockpit floor. There's plenty of room in that area. Great flying plane, you'll really like it. Jerry.

show871

Thanks Jerry! I did as suggested and wow, I am still WAY tail heavy. Retracts up, no gas. I really dont have much to move around, any ideas I really dont want to add weight. Hmmmmmmmmmmm 871

lesliehowell

Just add the weight or go with a bigger battery pack. I put mine under the green house in the nose. You need a extension to do it but it works fine and if that don't work just put a bag of buckshot in the nose. The nice thing about using buckshot is you can remove a few shot at a time to get it to handle like you want to.

And just remember if this is your first twin if you loose an engine just cut the throttle and land like you would with a single engine airplane that had a engine quit.

Sincerely yours,
Les

show871

Hey thanks....I have done a few mods to the tail to lighten it, and moved all my rx equiptment under the cockpit to hopefully reduce the added weight I will need (I will try the buckshot) It is my first twin.....thanks for the help! 871

modawg73

Had my maiden flight a few days ago, and only almost wrecked her once!

I had the nerve override my thought processes, and I took off with the flaps in the fully deployed position (i intended to have them on half). She took off fine at about 3/4 throttle, and climbed rather quickly, but didn't gain much airspeed. When I gave her more gas, she started to balloon upward, with a very high angle of attack (can you say 3-D with a B-25). Not sure of what was going on, I tried to give her more throttle and down elevator, but she was never quite right. About 100 feet up, she started to wingover (without me telling her to). So I cut the throttle and pointed to nose down, regained control of her and landed her immediately. On the approach I barely had enough elevator authority (i was on low rates) to keep her from plowing in but she pulled up to level flight about 5 feet off the ground. I put her down in one piece, then I started the shaking...

Turns out I never put the flaps up, so I was flying around with my flaps fully deployed. Not the brightest of things to do.

The next flight I took off without flaps, and she took more runway, but climbed out fine. A full size twin pilot told me that I was trying to climb too steep, that twins need to climb out much shallower, so I climbed her out very slowly. Got up to altitude, and flew around maybe 7 or 8 laps, then brought her in for some touch and goes before landing her.

A couple of observations about my first flights.

First, there was a significant torque to the left when I advanced the throttles aggressively, much more than any other plane I have (this plane has two Saito .62s for power). I am assuming this is a symptom of twins. I am wondering if I should add some thrust washers to the right engine to counteract that. Even turning in the air, I would have to consistently cross control with the rudder to stay on course (give right rudder on a left turn) I almost felt like she was wanting to tuck a wing under, and I was constantly fighting it. Not sure if that is my paranoia, or if that would really happen without rudder inputs. I'll check it out on my next flights.
Any thoughts would be appreciated.

Second, on landing the second flight, I was able to maintain a fairly high angle of attack while descending. Not sure if that is the wisest of courses, but it sure looked cool. Anyone had any troubles with that? She was under control the whole time, just with a nose high attitude (probably 20 degrees from horizontal). Anything that I need to worry about if I fly her that way?

Third, my landing gear rotated on landing. I thought I had tightened all the set screws, but apparently I missed the one that secures the strut into the wing gear. No damage, just need to remedy before the next flight.

So, on maiden, I would not recommend flaps unless you can be calm enough to remember to raise them Climb out at a shallow angle, and watch for the engine torque. Other than that, she flew beautifully.

Ken

lesliehowell

Ken,

I have been flying twins for about 15 years now and if you were going to add thrust washers here is what to do. When you are looking at the front of the plane make the right engine 4 degrees of thrust toward the right wing tip. Add 2 degrees of thrust to left engine towards the left wing tip. It sound strange but if you stand over the plane both engines should point toward that wing tip. IN other words they both point out and in toward the fuselage.

Sincerely yours,
Les