mikes68charger

My Feedback: (34)

Hey guys tomorrow is the day.

So do the flaps have any chance (need elevator trim)?

The factory rates are thos about a high rate?

Thanks

cosmo21

Anyone eles got RPM numbers to make me feel better?

My fear is the first time I few my Hanger 9 B25 electric with 12X4X3 props were bad, as I had to keep it a full power to stay in the air.

I was about to give up on my twin sycn but I got it working and it is great! I cant waite to get this big girl in the air.[/QUOT

I'm running Saito FG 21's, on 15x7x3, and it fly's well. By no means overpowered but nice and scale. I get about 8500rpm at max I think. I fly also at 1200 feet amsl, and we are in the tropics here. See density alt I would expect to be around 3000 feet.
What I'm pointing out is, you will have lots of power with the 180's. Don't sweat it man, just keep em both running.

Good luck, she fly's nice. Nothing hard about it.

Matt

mikes68charger

My Feedback: (34)

Well guys 2 great flight today! This is a great flying plane. I had to put around 8 clicks of down elevator to fly level wich is odd

The ASP 180 4c to gas sound amazing but if I was to do it again I would just use DLE20ra. These motors are picking up more power im at 9200 rpm with ma 15x7x3 blades. Wich is up from the 8500 when I started running the motors 3 days ago



Im grounded as one of my rudder servos is going bad.

tevans55

I had the same problem on my first flight. I cranked in about 10 clicks of down elevator. When I retracted the wheels I had to put in another 6 clicks. I mixed the retracts with the elevator so that when the wheels go up the elevator goes down. We are not the only guys that had this issue. I think it is an incidence problem built into the plane. Glad to hear your maiden went well.

cosmo21

Same, required some down trim, easily done. Didn't notice any extra tho after wheel retraction. Although I retract the wheels as soon as a positive climb is attained, so may have been cumulative. But not excesive..

Matt.

tevans55

Matt-
I decided to put CJM gear with Robart 5.25" wheels and brakes. Ended up with about 2 lbs. going aft when I put the wheels up. By the time I realized how much weight I was moving it was to late...had to live with it. I wanted close to scale size wheels and brakes. Sure is fun to fly.

Tim

cosmo21

Oh yeah understood.

On my ESM Corsair I decided against the 5 inch Robart wheels for that reason, and very$$$$ Using Dubro 5 inch instead, painted white, look the same.

She is good to fly this B25. I took the mufflers of the Saitos, sounds narly on a fly by.

Matt

mikes68charger

My Feedback: (34)

That is why I went with the 5.25 Byron corsair wheels for the b25 still sweet looking and even added air brake

Because of the huge rear wheels I just added a peace of 5mm ply under my nose retract as im useing the CJM gear also and it has a little nose down, I think be of this is why I had to hold full up elevator and to get it to rotate

My CJM gear was used and has a lot of side to side slop

The rudder servo issue killed 3 hours of my time yesterday as only one of my rudder servos would start shaking 1\2 in for no reason, I replace the servo first and it did the site thing so I then replaced the Y harness still the same thing, so then I replaced the 2 extension one at a time, and it still happening (lost my mind)

Put the original new servo back to as it was not doing it plugged right in the reciver so I figured it was a power drop issues put it back in and it still did it, got pissed and replace the servo with a different brand and all was good, put the plane all back together and tested it o e more time and the new servo was moving the wrong way

Lost my mind and opened it up and soilder\reversed the servo on the plane. But all is great now what a bad day

mikes68charger

My Feedback: (34)

Hey guys im a believer in being able to pick up any plan by the wings to carry it

Well I was going to fly the B25 today and put it together in our table, had a guy help pick it up and my side broke, it turns out both of my aluminum wing tubes are almost 1 in to short. So I used a old Trex600 boom tube and a peace of a stock DLE 55 side muffler to extended both tubes, I had to re poxy the fiberglass tube in the motor necklace

Just a fyi

F82FAN

My Feedback: (10)

I'm not too sure that it's a great idea to carry a heavy warbird by the outer panels, but it's a good thing you found the problem on the ground vs in the air!
Mine flew awesome every time and I wrung it out pretty hard (Loops, rolls, etc) with no structural issues (we re-built the center section after the maiden).

Fix and fly!
Good luck with her

kiwibandit

Well this discussion looks like it has been going on for some time.
I purchased one of these ESM bombers almost a year ago and have only just gotten around to assembling it. After reading thru all the issues that you guys have had to deal with, I am happy to say that my build was pretty straight forward. A quick run down.
A run over all formers and structure with epoxy to ensure that everything stays put.
Reinforce front firewalls to take my large engines. (Bit of an over-kill really but better to have power in reserve than not enough)
Engines are a pair of ASP 180 4c Have left them on glow for now. May convert to spark ignition later if required.
Props are Biela 16x10 scale 3 bladers. Look very much the part and are a good match for the engines.
Static rpms are 6800. Props are rated to 8000 so a good amount of revs left for it to unload in the air.
I'm hoping to be able to cruise around at 1/2 throttle or so for the scale look and sound.
Retracts are the electric esm units. These are better than their previous version but not by much.
Power is supplied via a pair of 3000Mah LiFe batteries thru a twin switch for redundancy.
Servos are Futaba for flaps and throttles. Hyperion digital for all others.
For the flaps, I used a futaba msa-10 4 bay servo mixer. Perfect for individual servo setups.
I have fitted functional landing lights into the wings which are mixed to the gear but can be forced off if required.
On-board glow drivers for each engine.
I chose to do the build as a no-frills aircraft so there are no guns or pilots or personal touches. I can hear your cries of dismay already.

I am currently waiting on the delivery of my other engine. Once installed and broken in - this big bird is ready to leave the nest.
I will post some photos of my build.
Hoping to get the girl airbourne on New Years day.
Only the C.O.G left to deal with after engine installed. There doesn't seem to be too many references regarding the cog. Can only assume that it is ok and doesn't require moving. I have several other esm birds and ALL of them needed the cog moved. Looking at the wing profile and where the cog is measured, my first thoughts are that it is too far forward. It will still fly but elevator control will be very limited. Is there enough left for the landing flair? I found one reply that mentioned setting the cog at 110mm measured at the point where the wing meets the fuselage. If some one has a defining answer - I would very much like to hear from them.

How many of these big birds are still airworthy out there? Of have most of them come to the sad demise that happens to nearly every modeler. Me included.

Greetings from New Zealand from the Kiwi Bandit.

kiwibandit

I didn't like the idea of a rubber band to hold the wing panel in place so I added a blind nut to the wing rib and drilled a hole to fit a bolt thru which is accessed thru the wheel well when the gear is down. It isn't too difficult and is very secure. I mounted all the electronics on the centre section. If it is removed from the fuse then only 3 connectors need un-clipping. Also keeps the number of leads to a minimum. One issue I had with the rudder servos, which I recall some one else had a similar problem, They would oscilate very badly. An easy fix was to remove the control horn and fit a very slim "o" ring over the servo output shaft. The small amount of drag created when the horn was fitted, prevented the servo from floating around the neutral point. The amount of lash in the servo gear train did not help either. The single lipo on the wing is used to power the led light in the outer wing panels.

tevans55

You're B-25 looks great. I'm sure you will have many hours of enjoyment flying it. I am still flying mine and love the way it flys. I just won Best of Show at our annual Warbirds fly in. If you have any issues with your electric ESM gear I have worked with Century Jet on the electric conversion for your gear. It is relatively low cost. CJM has also built an electric conversion for the Sierra gear for the Ziroli B-25's. Keep an eye on your ESM electrics. I used the recommended CG and have made small adjustments until the plane flew the way I wanted. My plane is 34 lbs. and I mixed a little down elevator when the wheels go up.

mikes68charger

My Feedback: (34)

I still fly mine with the 2 ASP180 converted to gas but I have to be honest I have been so cought up with turbine jets my b25 has just been hanging around as I had issues with my air brakes. I think I have around 15 flights and my motors are breaking in and need some more tuning

Did you add wood to the center section?

mikes68charger

My Feedback: (34)

I put my ASP180 going straight down

kiwibandit

I had already fitted the belly pant to the centre section when I saw the thread about the weak structure. Shame as it sounds like something that needs taking care of at the factory during the time of building. I will need to make a decision before I fly as to whether I go with the structure as is, or cut it up to do the additional beefing up of the framework. You mentioned that you went with the factory COG and moved it a little to suit you. Can I ask what your final measurement turned out to be?

mikes68charger

My Feedback: (34)

I believe I went back a 1/4in from stock. But make sure you add exstra throw in your elevator. There has been a few landings that I had to pull full up level off on the flare.

This plane flys very well like a big trainer.

I even had a engine out situation I was only 100 feet up and it died right in front of me. I forgot about the twin sync as it pulled the other motor back. I was able to glide it around and bring it in very smoothly. Made me I realize I could fly a lot slower

My only issue is if one motor is not pulling the same rpm on takeoff it can easily overpower the nose wheel to keep her straight on grass

But really I just needed to spend some more time tuning as one motor is pulling 1k more rpm

Eldher

Your B-25 is looking great. The 180's are really not too much power. I have 2 Saito 150's on mine, 16x8x3, turning almost 9000 RPM. It flies well, but not wicked fast. Frankly, with the amount of drag on this airframe, it just isn't going to go fast no matter what someone might put on it!

I have 70 flights on mine, weighs 30lbs. The stated CG is OK to start, but I have moved mine back to about 125mm. I use Robart retracts, wheels, and brakes.

I also fitted (glued) the belly pan to the center section originally. Over time this became a problem. The wing does flex and twist. As you have not beefed up the center section, it will twist all the more. On mine the glue joint would start to separate over time. I also added a bomb bay which required me to separate it from the wing.

As others have said, this is a great plane, easy to fly. Just watch the landings though, she is unforgiving if flown a little slow. At this year's Warbirds Over the Rockies I lost all aileron control on my first flight. I was impressed that the plane could be somewhat controlled with the rudder only providing both yaw and roll control. I did get the plane back, but a hard landing broke the right main gear out. Regardless, she is flying again ... now with ailerons working.

Eldher

Hey Mike! Love that pict of the 25 sitting between the 2 just fuses ... maybe you could bolt the whole thing together into one wild looking bomber/fighter thing!!!

tevans55

If I remember correctly I believe I ended up moving my CG between 3 and 5mm to the rear. I made the final adjustment about 2 years ago. Start with the CG in the instructions and go from there. Yours looks like it will be a lighter setup than Eldher's or Mike's or mine. Just my thoughts...I think you will do well to start with the recommended CG.

mikes68charger

My Feedback: (34)

Ya sweet. Im not a huge fan of the Century Jet Model retracts. The nose gear is great but the rears have almost no movement. But I was able to get my Byron 5in wheels in the rear. They are sweet.

The only other thing I would tell a new builer of this bird. Add some epoxy to the fiberglass tube inside the engine pods as the round aluminum tubes don't go into the wood on the inside of engine pods.

I lifted mine up by the wing tips once and this fiberglass tube let go.

Even with all that motor I couldn't believe how much batterys and led hap to put in the nose

kiwibandit

Hey guys - thank you so much for the insight and information you have shared. It is refreshing to know there are people out there willing to share experiences with others in the hope that it will save a model from destruction. Simple tips like C.O.G and how much elev to mix in may seem trivial but when your hard work is on finals, it may mean the difference between a bag of bits or a greased in landing. I used to fly with dual rates all the time but have changed to using expo after too many near misses by forgetting to go to high rates on landing. The great thing about our sport - it is soooo individualized. What suits one flyer will not always suit another. My other engine will arrive today so I will post a few shots of the fully assembled aircraft and hopefully a link to a youtube vid of the 2 engines singing their songs.

The Kiwi Bandit.

Eldher

Looking forward to to picts and video Kiwi! Spend plenty of time getting those engines set before putting her in the air. Can't tell if you've set up and flown twins before, but all of us spend time tweaking and tuning to get things right before flying. For me, I end up spending 30 minutes or more tuning at the beginning of the flying season getting both engines to the point the I feel they are right together. I can't even remember how much time I spent with the engines before the first flight, but my wife was getting jealous!

kiwibandit

Thanks Eldher. Wise words indeed. I did an OV-10 Bronco about 5 years ago which was also a KMP kit. It was fantastic to fly. I had it set up with twin 30cc gas engines. I spent an insane amount of time setting up the engines. Sadly, the trees on the approach to my flying strip caught me out after I had an issue with one motor losing revs. It would not recover so I pulled the pin on the ignition of both motors and turned it into a glider. It caught the top 6 inches of the trees. It was one of those moments where you think you have cleared the obstacle and then you hit it. My youtube page has the first few flights. I can post a link if you like.

The second engine arrived today so it was pulled apart to check for fod and also do a pre-oil of the internals. Tappets were reset as they were way too tight. Bolted to it's mount and away we went for 3 tanks of fuel. By the end of three tanks things were looking promising. Great idle and transition. A little bit of detonation was going on if I tried a burst of full power. Okay - stay away for now. I decided to fire up both engines together and see how close the two ran. I have run into a snag which is a worry to say the least. Start one, warm it up. Start the other - the first motor stops. Go back with the starter and re-start it. The second motor stops. Hmmmmmm. Never had this happen before. If I kept the glow power on all the time I could keep both motors running. If the revs stayed above 3500revs the glow was not required. Below that - it was a lottery as to which one would stop first.

Has anyone come across this issue before. I'm not sure if it is a fuel issue or harmonics affecting the barrel in the carby. Maybe floating up against the pre-load spring. Further testing will be required to track down the culprit. The fact of the engines continuing to run if the glow power is left on has me leaning towards a convertion to spark ignition.
I had been thinking about this option anyway so maybe now it will just have to happen.

The Kiwi Bandit.

kiwibandit

http://www.youtube.com/watch?v=oJSvx...sBKxOKh1vDUqDA

This is the link for the Bronco