LDM

My Feedback: (15)

Dose anyone know the correct size of what small pilots would look like to fit this plane .
I would like to add the interior and the pilots to this plane so I figure they could be sourced at a good train shop and painted correctly .

Anybody do the math on the cost of the batteries for those of us going eletric ?

wildswan

I reckon £200 (400usd) for 2 x Flightpower Evo 4cell 3700mah, thats whats going in mine.

LDM

My Feedback: (15)

Thanks wild

Hellcat716

My Feedback: (2)

Anyone getting one of these for your first twin? I was told not to get a warbird for your first twin. Any comments welcome. I currently am flying most of the Hangar 9 warbirds and would like to get the B-25.

kahloq

The first twin I flew was an ME-262 ducted fan. Followed by an A-10 ducted fan and then a P-38. The P-38 was the easiest to fly because of prop wash.
The B-25 should be fine for a first twin, but there are things you need to be aware of. when flying a twin and setting up motors. Using fuel powered motors, you've got to be very careful to get the throttle servos working almost identical....meaning same length of servo rod, etc. It is not usually possible to get both motors running at exactly the same RPM at all throttle levels(even with electrics). So, you can have a variance of between 0-500 RPM's and you'll be fine.
If one engine goes out, you HAVE TO REACT fast enough to prevent a yaw type roll over towards the dead engine. You either have to have a lot of rudder to compensate or simply shut the other motor down and dead stick the plane down(probably best unless you use overpowered motors).
I am sure other ppl will tell you things to keep in mind as well.

If your unsure about it, get an e-flite P-38 and fly that. It can be setup for rudders. Use a simulator to practice engine out situations too. After this, get the B-25.
I dont think its a problem though. You've got seemingly plenty of stick time of several warbirds, so its not going to be a problem. There's not many twin civilian planes out there(in my opinion) that are worth the money to put together if your a warbird fan to begin with.

wildswan

I agree, it's a perfect first time twin as it has a light wing loading.

The rudders should be more than adequate to compensate for an engine out.

I'm putting the two recommended e-Flite 46 motors.

I'm not sure of the servo configuration as the website doesn't say what goes where, it looks like some mini metal geared servos are required though?

I've flown the H9 Miss America with a Saito 100, what a nice set-up that is.

The H9 Spitfire and F-22 Raptor with brushless electric 4120 axi equiv.

And last but not least the H9 P-47 150 with Z26, nice and scale (and big).

Crikey, I seem to favour H9 don't I?

Jason

kahloq

The specs for H9 B-25 on Horizon's website actually give a rather hefty wing loading of 36.5 to 42oz per square ft.
Their single engine planes like the Spitfire have much lower wingloading........
Spitfire @ 8.5 pounds has a wingloading of 26.07 oz/sq ft (the 8.5 pounds is a little light for the Spitfire as it has a flying weight of 8 to 9.5#s.....at 9 pounds the wingloading is still only 27 oz/sq ft).

The corsair has a lower wingloading then the Spitfire as per the flying weights listed on HH's site. At 8 pounds, it has a wingloading of 24.5 oz /sq ft. My Corsair weighs 8.4 pounds and floats pretty well, but still requires some power to land without stalling. At lower altitudes, it might float better of course.

What I am getting at here is that the B-25 is not a light wingloading plane....HOWEVER...theres always a but...lol.............the B-25 is bigger. The bigger the plane, the higher the wingloading can be and still fly really well. So, at an average wingloading of 39oz /sq ft on an 80" plane, it should be fine for someone's first twin. Just keep power on(or some speed) when landing even with flaps deployed.

wildswan

Should be a nice floater methinks..

I wonder if the barrel roll in the vid is possible with the electric setup?

Have you flown the H9 Spitfire? The flaps really work considering they don't deploy loads, hardly any power with flaps down looks cool when doing low level fly bys. Only thing I think is silly with H9 aircraft is the metal wingbolts, I've ripped the blocks out a fews times and now resorted to nylon ones.

wildswan

First thing with the B-25 is to replace any wing bolts.

kahloq

I own the spitfire yes and have flown it a good number of times as well as the Corsair and H9 P-51. The flaps work yes, but dont rely on them all the time because ground swells can balloon the plane up with them down. The Spit is easier to land without flaps, but must be landed a little faster.

I do also have the FSK B-25. Obviously a much smaller plane, but mine has a rather heavy wingloading for its size(48" wingspan with a wingloading of 22oz / sq ft.)

wildswan

Nice looking planes. I live in Birmingham, UK. I fly off a grass strip, looks like you have a nice bit of tarmac.

da Rock

3 blades on an electric motor............. easy........... There is an application somewhere online the electric guys at my field use all the time. They would put in all the info to cover the use of that 2blade, check the results, and then match them with the 3 bladers they can find at the hobby shop. Reverse engineering at it's best. With electrics, "equivalent" is real easy to find.

kahloq

Its nice to take off from yes, but its a little short for landing(its only 250 feet long) and often times I do roll off the end into the grass/weeds/gravel. Better that then to stall the plane(which i ve done a few times....not a good thing).

wildswan

I've got my master airscrew 3 blade 13x8 props.

Stuck one on a test rig onto the e-Flite Power 46 motor.

14.8v 4 cell Flight Power Evo 20
60 amp esc

640watt @ 46amp

A little concerned on a couple of things:

i) two motors is only going to give me 1280watt for a 15.5lb model (82.5watt/lb)
ii) pulling 46amps, the motor is only goouing for 40amp cont, 55amp burst for 30 seconds

I know this is not really intented for aerobatics, will I be okay with this setup?

Jason

kahloq

These planes are not supposed to be areobatics and there is no need to have 100 watts per pound. Even with your numbers of 82 watts per pound is better then scale

I think it'll be fine. Horizon doesnt give a wattage requirement and does recommend 13x8's, but they are 2 blade APC props. Because of the 3rd blade your using, your getting more thrust(a good thing), but losing top end speed performance a little. However, a 3-blade compares to a 2-blade by reducing the diamter 1 and increasing the pitch 1. Sicne there are no 12x9x3's, you would use 12x8x3. Same pitch as your 13x8x3's, but they will spin faster, thus producing more watts and comparable thrust(hopefully). try testing one and see what you come up with.
The evolution glow motors used on this plane(H9s setup) only have 10.5x4x3 props. These are considerably smaller

wildswan

So I should be okay with 13x8x3's then?

kahloq

You should be fine. Make sure you do a good roll out to make sure you get the ground speed before trying to lift off. I think you'll be pleasently surprised at how well it'll fly. You'll be just fine. Test in the air and if you like the speed, then keep them. If you think its a little too slow, then change to the 12x8x3's as it'll give you a little more RPM's.

I have the FSK B-25 using Park 450's and the prop range is such that the 9x7x3's are smack in the middle of that as well. The plane flies beautifully. Its not a speed demon, but the B-25 is a bomber, not a fighter anyhow.
I also have a P-38 in this size and used 9x7x3's on it as well and only had park 370's on it. This plane also flew extremely well and looks so darn cool with the 3-blade props. I have tried other 2-blade props for more efficiency and top end speed, but, there hasnt really been much difference.
My point with these examples is, the watts isnt the be all and end of of anything. Yes, its a good helpful marker, but, alot of different setups will work and they dont have to be RENO racer amounts of power to fly a plane like this.

wildswan

Just a little update on the prop selection.

I put a 13x8 apc prop on the motor and it's producing 550watts @ 40amps. I can see sense in the prop selection on H9's behalf as the motor is only rated to 40amp continuous.

dbateman

My Feedback: (31)

I'm thinking about taking the plunge on this bird.It's an ARF and semi-scale at that, but with a little extra work you could detail this thing out very nicely. The wing loading isn't that light so i will keep an eye on equipment choices. For me a scale size 3 blade prop will be a requirement, so an engine upgrade from the E-flight 46 will be in order. Low Kv high torque, will have to do some checking around as i want to maintain a decent top speed as seen on the one flyby in video. Why are the oleos facing forward in the photos? How robust are the Robarts for this bomber? Will contact local Hobby Shop today to order. Doug

LDM

My Feedback: (15)

spoke to a some guys who did the numbers the eflight conversion is 6 pounds heavier then fule , the batteries will be $400 , charger if you dont have one will run $159 to $200 , then add the motors and speed controls and eflight is one heavy package on the wallet and the wing loading

kahloq

Ok...ummm. theres no way an e-conversion will come out 6 pounds heavier then a fuel version. Also, anyone thinking of doing an e-conversion on this size of plane most likely already has chargers, etc.
Lets run down the numbers:
Fuel setup
weight of a standard .62 4 stroke: 16.4oz with muffler
weight of servo to run throttle: .5oz
weight of pushrod/clevis and servo estension: .5 oz
weight of fuel tank: 1oz
weight of clunks(one for fuel pick up and one for fill line) : 1 oz
weight of engine mount: 2oz
weight of fuel lines: .5oz
total: 21.9 oz x2 and this is dry...no fuel in the tanks and using small .62 4strokes
total for both motors: 43.8oz(give or take a half ounce)
(note...a 2stroke .46 motor with muffler generally weighs 17oz so the numbers here dont change).

electric setup
weight of power 46 outrunner: 10oz
weight of esc(60-70 amp): 2oz
weight of batteries 2 x 2200 extreme 4s Tp (7.6 oz per battery) = 15.2oz
Total: 27.2oz per motor
total for both: 54.4oz

Ok....so your thinking the fuel setup has a 10.4oz advantage overall. Oh, but wait......you still gotta put fuel in the fuel tanks. EAch motor will have a 10 oz size tank(roughly...could be bigger though). So, how much does 10oz of glow fuel weight? Now double that and your well over that 10.4oz difference.

Sorry, but I suggest your source redo his figures....or get a new source.

The e-flite package will actually have a lower wingloading compared to a takeoff weight fuel setup and up to about the point the fuel tanks get half empty. After that, the fuel setup marginally becomes lower in weight.
Hardly anywhere close to 6 pounds

Now, for someone putting in gas motors, their wingloading is going to be a lot higher, but the motors dont need as large of fuel tanks thus less overal fluid weight needs to be carried. However, the gas motor itself usually weighs a good 15oz or more then a 4stroke motor.

CorsairJock

My Feedback: (90)

Gotta agree: I have 2 Hangar 9 Corsairs. Corsair 1 is electric powered (AXI 4130/16, 6 S 6000 mAh LiPo), and weighs 8 lbs, 6 oz READY TO FLY. Corsair 2 is Saito .91 powered, and weighs 8 lbs, 5 oz BUT WITHOUT FUEL.

I have my electric Corsair setup with DynaThrust 14 x 8 (2 blade) prop. Pulls about 28 amps static, or just over 600 watts (IN) gives about 70 watts/lb. Performances is REALLY Good: short takeoff and capable of those big loops. I get over 15 minutes of flight time per charge, usually broken up into two 8 minute flights.

The motor and speed control combo cost less than the Saito .91 which powers the fuel powered one.

I use my $120 Astro-Flite 109 charger, which is about as good as it gets, and made by the company that practically invented electric powered R/C aircraft, to charge my $160 pack

But the bottom line: using todays LiPo batteries and brushless motors: an electric powered will not usually weigh any more than a comparable fuel powered one, and with no sacrifice in flight performance. That is why they are suddenly becoming so popular. In fact: 1/2A RC is all but dead, having been replaced by small electric powered aircraft which will outperform the .049 powered RC planes

And then there is the reliabilty factor, which is SO much more important in a twin: electric motors RARELY fail compared to fuel powered ones.

LDM

My Feedback: (15)

I appreciate that , this is what happen I was in a very big hobby shop in Orlando , named Graves hobbies , they seemed to know there stuff and they told me that they did the numbers and it was 6 pounds heavier . I was discourage becauee this would be my first e-flight conversion and no I dont have a charge because I have always done glow and only small eletrics .
Based on the fact that this is a twin , I really wanted an e-flight version , sounds promising now that you have given me the facts , any more advice would be appreciated ,
I was thinking of getting the astro flight #109 lithium charger for $129 does up to 9 cells lipo and adding a blinke cell balancer for this plane .

frednjess

I'd love to get this bird! I checked United Hobbies for the electric parts. Dirt cheap! $40/motor, $42/80A ESC, $65/3200mAh 4S lipo. About $300, TOTAL! Air retracts for $130. Yeah, I know shipping will add a bit, but only about $30. That's still only about half of what it would cost state side. That would be a 80" B-25 for under $900. Can't beat it.

LDM

My Feedback: (15)

United Hobbies ????????????[X(] motors for $40 , ?batteries for $65,[X(] are we talking about the same plane --if so please share details ????