CCFPILOT

Regarding servo mounts;

The only problem I had with servo mounts coming loose was on the rudders. The servo mounts on both rudders had come "unglued" after how many flights, I don't know, but they were both loose. The only thing holding the servos in was the tight fit of the servos in the horizontal stabilizer. I added more glue. I think I will go out and check the rest of my servo mounts.

flaviosi

RCGuy,

In which mode are you running the 401? Rate or AVVS?

For the purpose of using it on the B25, I'd definitely recommend using it on "rate" mode. If you try to use it on AVVS during flight you will crash.

Flavio

flaviosi

Normand,

Long time, no talk!

I saw somebody answered the meaning of ROFLOL... Anyway, I've just finished building my B25 with electric engines and sound sim. Sound sim is installed on the nacelles (I'll send pics). Now, I'll be doing some weathering on it and adding some nice stuff, like Spider Tim's...

Nice talking to you!

Flavio

RCGuy41

Normand,

Hi, thanks for the suggestions; I'll be heading to the field tomorrow for some flight testing. I'll turn the gyro to AVCS for take off then select heading hold once airborn. The sequence I have been going over in my head has been radio check, startup, RPM check, taxi, half flaps, power up, 1/2 way down the run way start to rotate, 3/4 down the runway start lifting off the field, gyro to heading hold, gear up, flaps up, and then enjoy the flight. If I have an in-flight emergency; say a left engine quits, the bird will yaw left, the gyro will sense the yaw and kick the rudders right.

Brad

RCGuy41

Flavio,

Thanks for the warning; since early this week I have been reading material and getting into Futaba's GY401 gyro manual. I plan to use AVCS for take off, and if I need it on landing also. Once airborne I am immediately going into heading hold, the rudder will react normally once in heading hold. I don't need to loose $2,000 dollars plus the time that went into building and some modifications.

Brad

RCGuy41

A general note to all,

Before I made my last set of flight last weekend, I received a set of aluminum main door levers from a gentalman from Port Washington Nwe York. The levers were exact replacement parts for the ply main door levers. Read below, is from the June RC Universe TF B-25J article.

A wooden bell crank that is made out of hardwood ply operates the gear doors. While the original wood doors are very durable some may find that repeated use over a long period of time may wear out the wooden doors. With this in mind one of our RCU members had made available a set of aluminum bell cranks that can be used in place of the stock wooden ones. They are available for a cost of $10, which includes shipping. If you are interested contact RCU member Mike-Rc (gear doors may be found here) to get a set of these bell cranks. I picked up a set so that I could show them here in this review.

Brad

camdyson

See early in the forum - there's pics of these bellcranks - a good investment.

Well, finally dragged her out of the workshop (now that was another story.....) an put all the bits together - nice. Took a few happy snaps, then fuelled her up for the engine break in. I was getting around 8500-8600 rpm on the MAS 12x8x3's with new OS 70 FS II's, sound about right for starters? Don't plan to test fly with the 3-blades, I'll use the APC's for that.

Both engines running together and resonating was a very cool sound (after tuning solo first) - boy, that Lancaster is gonna sound awesome...

Here's a few pics (sorry, there were no nubile wenches in bikinis hanging around, maybe next time.....) Next step is to set the throttle curves on the JR 9xII for both engines, balance, then out to the field. Oh, the Olive Drab isn't even close - everything I tried was a c#*p match, so in the end I went with the "it's a warbird - it doesn't have to match" excuse and used what was handy.

Cam

toreo

Cool pictures!
Camdyson, could you explain, how you do that? which airbrush? which color?
How you prepare surface??

Normand
I tested vp20 on my mitchel. I put 1 pump into 1 engine. I spent many time for tuning this pump.I tryed many variants with or without back line. It work great, but my fl-70 have air-bleed carb without idle needle. I minimize productivity of pump, but anyway on idle engine is too rich. on midle and hi rpm it work absolutle great.
When i get almost stable pumping engine, i test that with 2 working engine. No, absolutly, no relation on engine to other engine. My pump work on minimize productivity, and it work great. I teste in up,down, left, rigth position - it doesnt matter.

Now i am plannig put carb from os-fs70.

camdyson

Thanks Toreo,

I did similar to Fytrjok earlier in the thread - try about p39?

First I added aluminium panels and leading edges using aluminium tape like Flitemetal, plus some lithoplate for things like the fuel caps. Next all the decals were applied. After that, the whole lot was rubbed down with 400 grit wet-and-dry. Then I wiped an etch primer called ESP (like Prymol) all over to prepare for paint. Next I sprayed all the added metal panels with a small airbrush in Humbrol enamels - bit small for the job but it got done eventually.

O.K, next all the panel lines were drawn on with black "sharpie" pen using various rulers, circle guides etc. Then the fun starts:

All the panel lines had chipping added in Humbrol aluminium paint with a fine brush. Stone chipping was added all over the same way. Then I used the same hobby airbrush (a cheap double-action one) to lightly spray THIN black over all the panel lines, followed by the exhaust stains in brown first then gray over the top. All the screws etc were painted too of course.

Oh, all the canopies, turrets etc were masked off before started painting.

Finally, once all the paint was done, I sprayed on a coat of satin polyurethane varnish to seal it all, using my bigger touch-up spray gun - matt would have been better but I couldn't find any.

And that's about it. If I was doing it again I wouldn't use the primer - it made the clearcoat patchy, and Fytrjok didn't seem to need it on his.

Good fun - I'll be doing it on another ARF sometime for sure. I've attached a few pics of the aluminium added.

Cam

toreo

thanks, Camdyson. �fter end of this flight season i want to make my mitchel like yours.

norm

Toreo,

I have no doubt about the result of the pump working great on the engine setup you have. The only problem that may be is that at any time the oscillation may offset itself as explained by "Perry pump" manufacturer.

When the osciillation cut off happen, the pump cut the engine fuel intake and cause it to quit. It may be a good idea to have the bypass installed in any case, and use the pump to activate fuel flow. It will be less dramatic to have the pump cut off and still have fuel flow from the bypass.

In order to correct the rich setting you have at idle or low speed, you may whant to try and install the "Iron Bay Regulator." http://www.ironbaymodelcompany.com/i...es/Page438.htm

That will correct the demand problem and you set full flow on the pump.

Hope that may help you,

Normand

toreo

What you thing about VP-30 for air-bleed carb??

norm

Toreo,

I personally think it would be a better installation in anyways. The installation would be as reliable as the exhaust pressure you had with the mufflers on, hoping you removed them, no need for the extra weight! If you install the VP30, it is not only recommended but safer on 2 engine aircraft. The airbleed carb is tricky but your fuel flow will be constant with the VP30 and will enable you to set up your low end correctly.

Make certain that you use crankcase pressure and T going to 1- atmosphere and 1- to the VP30. The pipe must go up to the VP30 to drain down when flying or not flying.

Hope this help

Normand

jdhughen

My Feedback: (1)

Norman,

At your suggestion I contacted Gary Conley at Precision Engines (Perry Pimps) last week and described my installation using the twin side mounted Saito 72's, Dubro anti-vibration mounts, and the V-20s. He replied...

I will have to make a bracket since the stock crankcase bracket won't keep the pumps "parallel with the wings" in a side mounted configuration. All that said...

I inquired about this pump thing over on the "Twin & Multi Engine " forum and it was recommend by most to stay away from pumps of any type and to keep it as simple as posiable, add a nipple and go with muffler pressure. One actually suggested going straight carb vacum with no pressure ! I'm not going to do that but I am going to test adding the nipple just after the bend in the 90 deg header pipe where the flex pipe attaches. I'm not totally sold on that idea either since there are several things that can effect tank pressure at different stages of a flight. Have you any experience using a regulator of some type with muffler pressure to help even things out ?

I'm only about 35% complete so far so I have some time to figure out which way to go.

Thanks

Joel

norm

Joel,

I'm puzzled by the answer you got from Conley precision because I called several times for different issue ans got to this subject a few times 2-3 and I was told no go with 2 x vp20.

Nevertheless my installation is flawless after approx 80 flights. Never had problems. As for regulators call Iron Bay and they have a demand regulator that does a great job.

Normand

fytrjok

My Feedback: (2)

Cam,
Great job on the finish! It's pretty amazing how good we can get these to look with not alot of effort. I, like you had a ball transforming this ARF into a battle hardened veteran. I like to think we're more artist than builder when undertaking a project like this. Enjoy the compliments you're bound to get at the field! I especially like the response when I tell them..."Nope, it's not glass and paint, it's the stock Monocote and a little elbow grease!" The looks I get are wonderful!

norm

For every one,

I have noticed a "play" in the wings developing around the fuselage, ie: the wing is loose at the root and move 1/1/ to 1/8 inch up and down at the leading edge and the trailing edge. As if it is becoming loose in there. I did not have any hard landing that may cause this but I intend to glue the wing to the fuselage ans see if I can reinforce the joint inside the fuselage around the tubes bypasses. I suspect the wood is "mellowing" around this area of the fuselage.

Will let you know my findings and if anyone has the same situation please let me know or if you corrected it what you did.

Normand

jdhughen

My Feedback: (1)

Norman,

I think it might have to do with the mounts. With the mount and engine bolted together each "shaking" it own pump free from direct connection to the Fuse I guess they figure it's enough isolation ??? at any rate I'm going to test it well before I do either. If you have 80 flights with no problems I'm temped to return the v-20s and go with the 30s, our engines are very similar. Did you have to adjust the flow rate from the factory setting on your 30's ?

Thanks

Joel

norm

Joel,

What I did was explore at first then found that the bypass as indicated in the instructions from perry pump website, the link is a few postings away, in the last few weeks, but the pump was too rich directly to the engine., The bypass enabled enough flow to let the engine pick its own fuel. The 4 stroke does not need any fuel pressure as long as the fuel gets there. There is enough vacuum created in the carburator to aspire fuel to the engine. It is also desirable to let the engine aspire the fuel it demands. There is not enough aspiring actionj when the fuel tank is half empty and less because the uphill is too hard for the carburatop to pull up the fuel "uphill." The VP30 pump enables a constant fuel flow to the carb and the excess pressure back to the tank. I presume 80% of the fuel pumped returns to the tank. With the pump the fuel is always there and the engine is running extremely well from top to bottom of the tank.

The pressure has been increased intentionally to increase the "current" of fuel near the carb inlet. Thwe VP20 would do just the same if the counter vibration of the other engine was not a threat.

I personally think the VP20 is desirable and easy to install and all my other planes 4 stroke single piston work with the VP20 and that is 11 of them. I got 5 YS engines with their own pumps and they are very very X 1000 hard to tweek and tune correctly. On a 4 stroke, the pump enable you to run at a perfect setting from top to bottom of the tank and prevents "rich" low power full tank run to "lean run" near empty damaging the engine. Both those settings rich and lean are responsible for "dead stick" or the cause of it. The pump eliminate those critical stage of the flight and enable you to run with larger tank and (bigger the tank worse the problem too rich and way too lean near empty, using muffler pressure). Some other will say yeah but the pump is bound to fail. They are right but, the more sheeps, the more you watch, and the richer you are....in this case you have many benifits, better run, you prevent glow plug damage running too lean and you may run straight pipe! ( undisputable must on a warbird, and an honnor for this B-25 )

If you do regular verification and maintenance, this will eliminate the possibilities of avoidable "sudden failure"

You only have to take the time, is'nt it what this whole hobby is about...

If you ask me, I would do what you are tempted to do because my results are good with the VP30. I will call jeff at Conley Precision and ask him again to make sure he is not just saying anything or if I misunderstood, but I recall he mentionned to me VP20's work with engine vibration and this tuned vibration from 1 engine will cause the pump to rotate, just like if you put a glass on a speaker when listening to loud Pink Floyd music the glass start to turn on certain harmonics, but different harmonics will cause the glass to stop turning and even bounce or turn in the opposite direction. My understanding is that the VP20 as explaned by Jeff, (I think that is his name) will be affected to the "offtuning" (just made up this word, I'm French Canadian this makes sense to me) ...offtuning...of the other engine"

Normand.

toreo

I make decision to sell my OS-70FL and buy saito 72 or 82.

more people have 82 on B25, but I have doubt about 82. My competition program is 10 minutes. with os70 it use almost full tank. I think 82 without muffler have more fuel consumption...

About power... with os70f with mufler and 12x6x3 MAS, l have more than enough power for scale flight and maneurs in any weather condition.

Wich 3 blades prop is best for 72, 82?? 12x8?? 13x8??

norm

Toreo,

The 12 x 8 is the best with the 82 Saito. Full throttle will give you approximately 9700 RPM. You will get about 10 minutes before dry from the tank at full throttle.

With Saito, there is only 3 good choice in small single cylinder engine. the 62, the 82 and the 125. Why get the 72 if size and weight is the same as the 82? The 82 is so much more powerful that I wonder why some would buy the 72. The same as the 91,100, 115 and 125. They practically weigh the same, are the almost same size if not only for 1 or 2 mm difference and weight is only a few grams difference...5 feet away you could'nt tell the difference.

It is best to go for power.

I'm detailing and putting together another B25 with the saito 100T, twin cylinder engine in the winter. this one will be for show. those are nice and was my first idea.

Normand

toreo

thanks, Normand !
i know about 100T, i read rc-don.com. But is too expensive for me.

100T is twice weght against 82. + 800 gr with 2 100T.... but sound...
Ill be think...

norm

Toreo,

It is lighter w/o mufflers!

Good luck,

Normand

flaviosi

Normand,

Will the 100's fit in the cowl? I like the idea...


Flavio

elojim

Yes,

have a look here : www.rcdon.com