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Author Topic: Electric Banshee nose length and C of G position.  (Read 829 times)

Offline redout

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Electric Banshee nose length and C of G position.
« on: June 20, 2022, 12:24:07 AM »
When electrifying a Banshee, and having chosen possible motor, battery and esc positions, assuming the correct centre of gravity has been observed, is it a problem if a very short fuselage nose length results ? (It may be around 4 inches from leading edge to prop.) Perhaps something to do with the gyroscopic effect of the propellor acting too close to the C of G of the plane ?

Also when people say electric set-ups can have their C of G's more forward than for I.C., how much more forward is typical ? For an electric Banshee, does 1/2 inch more forward than the position shown on the plans for an I.C. engine sound about right ?

Thanks,

Richard.
« Last Edit: June 20, 2022, 01:45:11 AM by redout »

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #1 on: June 20, 2022, 06:44:59 AM »
When electrifying a Banshee, and having chosen possible motor, battery and esc positions, assuming the correct centre of gravity has been observed, is it a problem if a very short fuselage nose length results ? (It may be around 4 inches from leading edge to prop.) Perhaps something to do with the gyroscopic effect of the propellor acting too close to the C of G of the plane ?

Also when people say electric set-ups can have their C of G's more forward than for I.C., how much more forward is typical ? For an electric Banshee, does 1/2 inch more forward than the position shown on the plans for an I.C. engine sound about right ?

Thanks,

Richard.
What motor/esc/timer are you going to use?  4" seems a bit short.  The rest of the plane must be very light.  I have yet to get a definitive explanation why the CG on an electric is forward of the same plane powered by IC.  Lots of theories.  Concentration of weight seems to me to be a part of it at least.  Mine have come out 1/2" to 1" fwd.  If it were mine I would shorten the nose no more than 1" and use the battery to balance it 1/2" ahead of the plans for starters.  "That's just me, and I could be wrong." y1

Ken
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Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #2 on: June 20, 2022, 08:46:48 AM »
... It may be around 4 inches from leading edge to prop. ...

A properly-selected electric system should weigh about as much as a "modern" Schnuerle-ported stunt engine and a full tank of fuel (I.e. OS 25LA and a 4-ounce tank, for that plane).  That, in turn, should result in a nose that's about the same length.  Granted, the Banshee has an extra-long nose by current standards, mostly because it was designed for an unmuffled Fox 35.  Even taking that into account, though, 4" seems short.  Are you sure you're not equipping it with way too much motor or battery?

... The rest of the plane must be very light.  ...

And if it is, you can use even less motor & battery, because power use goes with airplane mass for any reasonable stunter.

I'd put the CG about the same, or no more than 1/2" forward.  Then make sure you can adjust it.  Some of the top experts are running their CG way forward -- some aren't.  Probably, if you have to ask, you may as well just put it where it'd be on a slimer with a full tank of fuel.
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Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #3 on: June 20, 2022, 09:08:27 AM »
if you have to ask, you may as well just put it where it'd be on a slimer with a full tank of fuel.
Aren't most plan CG's measured dry?  Still like to know what motor and battery he is planning to use.  A short 28xx motor and a 2200kwh 25c 4s battery should be sufficient.  Especially if it is light.

Ken
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Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #4 on: June 20, 2022, 11:54:22 AM »
Aren't most plan CG's measured dry?

Yes, which makes the conversion a challenge.  It's probably about 1/2 an inch...

Still like to know what motor and battery he is planning to use.

+1!  If it's the right motor for porky Legacy or Impact then it's the wrong motor for a Banshee.

A short 28xx motor and a 2200kwh 25c 4s battery should be sufficient.  Especially if it is light.

Well, I do have a 48 ounce Twister in my stable, for which 2200mAh and four cells would be insufficient, or very barely sufficient.  But if it's a reasonable weight Banshee, then yes, that would probably be enough.
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Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #5 on: June 20, 2022, 12:29:38 PM »
Well, I do have a 48 ounce Twister in my stable, for which 2200mAh and four cells would be insufficient, or very barely sufficient.  But if it's a reasonable weight Banshee, then yes, that would probably be enough.
Probably right.  Mine was 51oz.  I got the full 5:40min from the timer but I could feel it weakening in the last loop of the clover.  2800 or thereabouts is probably better.  I flew mine once on a 5s and it was massive overkill.  Sometimes I think that there is just as much stuff to learn for electric as there was for IC.  With a Huben you can switch batteries and keep the same lap times.  Did that with a Fiorotti and went from a 5.2 to a 4.7 switching from a 5s to a 6s.

Ken
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Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #6 on: June 20, 2022, 01:21:27 PM »
Sometimes I think that there is just as much stuff to learn for electric as there was for IC.

Oh yes.  I switched to electric when I did because I could either spend a bunch of $$$ on electrics and time learning all the tricks pertinent to CL, or I could spend a bunch of $$$ on tuned pipes and time, ditto.

I kinda like the sound of an electric plane, so...
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #7 on: June 20, 2022, 03:20:51 PM »
Oh yes.  I switched to electric when I did because I could either spend a bunch of $$$ on electrics and time learning all the tricks pertinent to CL, or I could spend a bunch of $$$ on tuned pipes and time, ditto.

I kinda like the sound of an electric plane, so...
And 60 years IC experience makes you a freshman newbie when you punch your first timer start button!

Ken
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Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #8 on: June 20, 2022, 08:00:52 PM »
Ken, after a lot of research ( you are not wrong about the level of knowledge to be acquired for electric ! ), I selected the Turnigy 3542-1000 ( about 140 g / 5 oz. ), Zippy Compact 2800 4S battery, Turnigy Plush 60 A esc (could change) and Hubin FM-9 timer.

I am fairly confident that for a Banshee, there is nothing way out with this spec. I am only using the 60 A esc at the moment ( still in the set-up stage ) because I ran some trials on the weekend using a watt-meter and was seeing around 42 A ( and 616 W ) with an APC 11 x 4.5 EP at 12 150 rpm, at 70 % power setting.

I think with this set-up, I am going to need the heavier 2800 mAh battery ( 10 oz. ) as opposed to the 2200 ( 7.5 oz. ) to get enough run time. And as a general comment, yes, the plane so far seems quite light to me (the airframe).

And Tim, I understand totally why you asked if the short nose may have been due to too much motor or battery weight but you can see the motor is "about right" and if you look at the photo, this short nose situation is being caused by the battery position - it is kind of tucked neatly out of the way where it is, but of course there is no battery weight behind the L.E., causing the short nose. I placed the battery here, as at only 111 mm long, it fits the vertical space a little nicer than having it lie partially over the wing. ( Also I don't want to cut into the L.E. to fit the battery if I can help it.)

The set-up, as shown, is 4.5 inches from L.E. to prop. and the CG is on the balance point shown on the plans.

Does anything look way out with this arrangement ?  It is only the second power system I have been involved with.
« Last Edit: June 20, 2022, 10:29:42 PM by redout »

Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #9 on: June 20, 2022, 08:06:41 PM »
p.s. How do I add more than one photo to a single post ? When I selected the second photo in the post above ( "Attachments and other options" ), it replaced the first one. Thanks.

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #10 on: June 20, 2022, 09:49:32 PM »
Just for reference, I am flying the plane in my Avatar with a 3515 and a 44amp esc. It is 65" span 690 Sq" and weighs 62 oz.  It is not even close to being under powered. 

Ken

Under the Attach: control there is a link to add "(more attachments)".  Click on it!
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Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #11 on: June 20, 2022, 10:35:31 PM »
Just for reference, I am flying the plane in my Avatar with a 3515 and a 44amp esc. It is 65" span 690 Sq" and weighs 62 oz.  It is not even close to being under powered. 

Ken

Under the Attach: control there is a link to add "(more attachments)".  Click on it!



Are you using 4S batteries with this set-up ?

I am starting to suspect from my motor run figures that I may have a little bit more motor than I need but at 140 g, it is still seems appropriate for the Banshee, I think. I have seen others on this forum using about this much motor. Also maybe I have a little too much prop. at 11 x 4.5 ( APC ) but once again I have seen others using up to 11 x 5.5 ( APC ) on the Banshee. So will probably try this set-up unless any advice to the contrary results.

Thanks for the attachment info.

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #12 on: June 20, 2022, 11:47:42 PM »
Are you using 4S batteries with this set-up ?

I am starting to suspect from my motor run figures that I may have a little bit more motor than I need but at 140 g, it is still seems appropriate for the Banshee, I think. I have seen others on this forum using about this much motor. Also maybe I have a little too much prop. at 11 x 4.5 ( APC ) but once again I have seen others using up to 11 x 5.5 ( APC ) on the Banshee. So will probably try this set-up unless any advice to the contrary results.

Thanks for the attachment info.
The one nice thing about electric is that you can run them at just about any RPM you want and they don't seem to care that much, unlike IC which will "bite you" if you get too far out of their comfort zone.  The FM-9 is a great timer for fixed RPM.  To answer your question, I am using TP 5s 2800's.  You were correct that a 4s 2200 will be too small for that motor.  They run best of 5s and 6s batteries.  You are in the ballpark on props.  I ran 11x 5.5 or 6.

So, unless you want to go out and buy another motor, you have your system.  A bit heavy but it will allow you to tame it.

Ken
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Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #13 on: June 21, 2022, 12:53:02 AM »
That's interesting about you using 5S batteries. I guess that's how you got your current draw low enough to use a 44 A esc.

And it's good to have confirmation on approximate prop. size. for the Banshee.

Thanks Ken.

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Re: Electric Banshee nose length and C of G position.
« Reply #14 on: June 21, 2022, 02:44:30 AM »
Here's my $0.02.

I would use a Castle Edge Lite 50 or a Castle Talon 60 ESC with the Hubin FM-9.
That 11x4.5 will probably be terrible, lack "punch" and eat up your battery, (in my opinion)
I recently switched from a APC 11x5.5 to an APC 12x6 trimmed to 11".  Battery mah draw went down considerably with the trimmed 12x6, and the airplane has much more authority everywhere in the pattern.  The trimmed 12" prop is much stiffer than the 11x5.5, which may contribute to the change in performance.

My draggy 55+oz converted Pathfinder-oid is definitely maxing out the mAh draw from what I would consider appropriate with the 4s2800 TP battery. 
It does the deed, but I have it setup for only a couple extra laps after a full pattern.  I will be trying the smaller 2820/970kv motor to see if the 1.16oz off the nose translates to any better flight corner performance and/or reduced battery draw.

Pathfinder 620 sq.in.  55'ish oz, Cobra 2826/930kv, Castle Edge Lite 50 ESC, ThunderPower 4s2800. 63ft .015 lines.
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Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #15 on: June 21, 2022, 05:53:45 AM »
I do have a Castle Edge Lite 50 and I would like to try some flights with governed mode ( which my Turnigy esc's can't do I am told ) so that is on the cards. Also I will start to experiment with cut down props. Thanks Brent.

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #16 on: June 21, 2022, 06:35:38 AM »
I do have a Castle Edge Lite 50 and I would like to try some flights with governed mode ( which my Turnigy esc's can't do I am told ) so that is on the cards. Also I will start to experiment with cut down props. Thanks Brent.
The Edge Lite 50 with the FM-9 is a really good combination.  I think the settings for both are on the site somewhere.  I used them with a Cobra 2820/12 on my Twister,  which is about the same as a Banshee, and a 2826 on a converted Nobler.

I would go with the lighter components and keep the nose longer.  Just me.

The Spin 44 ESC recommendation came from local old time electric folks choices.  It is border line but so far I have stayed on this side of the border.  My new ship is being built for 6s batteries and I have a Spin 66 in it.  As an FYI, I have flown the Spin 44 with a 6s battery with no issues.

Ken
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Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #17 on: June 21, 2022, 09:12:30 AM »
p.s. How do I add more than one photo to a single post ? When I selected the second photo in the post above ( "Attachments and other options" ), it replaced the first one. Thanks.

Under the space to push the "choose file" button, there's a tiny link that says "(more attachments)".  Push that, and you get another spot to add an attachment.

The motor you've chosen has a power rating of 770W.  If true, that would be good for a 70 ounce plane.  A smaller motor would work just fine.  The mostly-reliable rule of thumb is to multiply the airplane weight in ounces by 11 watts/ounce to get the maximum motor power used.  For the HobbyKing motors, since they don't tell you both maximum and continuous power, and since they're cheap, just assume that their listed power is maximum power.  You may find a 26mm diameter motor is easier to fit.  But -- that motor will work fine, it just adds extra ballast.  The batteries are about right.

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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #18 on: June 21, 2022, 09:24:37 AM »
Just a note for the newbie on the whole "my motor is underpowered" thing.

Electric motors are different from IC engines, in that they -- more or less -- generate a given RPM for a given input voltage and Kv rating.  So on your plane, with the same prop (probably an 11x5 or 11x6), a giant 3590 (if they make such a thing) motor with Kv = 1000 would turn about the same speed as a pancake 3510 with Kv = 1000.  The differences are that (A) the little motor will bog down ever so slightly more than the big motor, and (B) the little motor will get way hotter, and (because I chose an extreme example) may even fail before you land.

So unless you burn up the motor in flight (I've done that :o) you won't notice a too-small motor until you land and check the temperature.

If all the manufacturers are being honest, then it's the combination of motor Kv and the battery voltage that determines the top speed that the motor can turn.  Once you've got the motor turning the right speed, the actual size of the motor and the amount of air you run past it determines whether it'll be a healthy motor in the long run.
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #19 on: June 21, 2022, 09:34:08 AM »
Good for you for checking the balance beforehand!  I'd probably put landing gear on the thing and at least mock up the pushrod in back, but you're probably close to correct.

After I switched to a motor that's rated for 450 to 500W to lighten the nose a bit, I think I'd just make the shortest nose I could reasonably make (with heavy emphasis on "reasonable"), without worrying about the plane being nose heavy.  Then I'd put a weight box in the tail to get it to balance right.  Yes, light weight is good.  But a super-light plane that you never want to fly isn't.

I've seen folks move the motor up a bit, and mount the battery underneath in a "chin".  I've also seen folks put the batteries inboard.
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #20 on: June 21, 2022, 12:01:52 PM »
After I switched to a motor that's rated for 450 to 500W to lighten the nose a bit, I think I'd just make the shortest nose I could reasonably make (with heavy emphasis on "reasonable"), without worrying about the plane being nose heavy.  Then I'd put a weight box in the tail to get it to balance right.  Yes, light weight is good.  But a super-light plane that you never want to fly isn't.

I've seen folks move the motor up a bit, and mount the battery underneath in a "chin".  I've also seen folks put the batteries inboard.
I am not disagreeing with Tim because much of what we do is personal preference and your style will work for you if you master it.  I like the longer nose for flight performance reasons.  The longer nose (for me) locks out of corners better than a short one.  However the Banshee nose is overly long.  Shortening it by an inch or so is fine.  My starting point for nose length is 1/2 the tail moment and I normally go a bit longer.  I don't like concentrations of weight (tip excluded) so put my batteries parallel to the body.  Tim's suggestion to put them inboard is wise.  I have, out of habbit, put them on the outboard side and regretted it.  From now on they go inboard.  In a hard turn that little battery weighs over 10 pounds and is trying with all of it's might to rip itself from the mounts.  Don't ask me how I know.  Now there is the problem with horozontal CG when you mount inboard so I suggest cutting a hole for it through one side to the outboard doubler.   ESC and Timer go outboard.  Plenty of room.

Ken
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Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #21 on: June 21, 2022, 01:50:57 PM »
... I like the longer nose for flight performance reasons.  ...

Well, now I can invoke the power of weasel-words.  For you, "reasonable" means a longer nose that the shortest that you can possibly get it.   ;D
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #22 on: June 21, 2022, 03:03:27 PM »
Just to clarify, "inboard" meaning on the pilot side of the ( profile ) fuselage ?

I imagine it has to mean that, but how does placing a battery inboard give an advantage over placing it outboard, as far as improving fore and aft C of G and nose length ? Because if the battery is inboard with all the room to itself, you still can't move it forward up the nose because the C of G will move too far forward.

The problem with my current set-up is I can't move the battery back far enough, hence the short nose. ( Unless I put the battery over or through the L.E. ).

Thanks for your all your insights !


Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #23 on: June 21, 2022, 03:24:00 PM »
Under the space to push the "choose file" button, there's a tiny link that says "(more attachments)".  Push that, and you get another spot to add an attachment.

The motor you've chosen has a power rating of 770W.  If true, that would be good for a 70 ounce plane.  A smaller motor would work just fine.  The mostly-reliable rule of thumb is to multiply the airplane weight in ounces by 11 watts/ounce to get the maximum motor power used.  For the HobbyKing motors, since they don't tell you both maximum and continuous power, and since they're cheap, just assume that their listed power is maximum power.  You may find a 26mm diameter motor is easier to fit.  But -- that motor will work fine, it just adds extra ballast.  The batteries are about right.

Forgot to say - that was very helpful. Thank you !

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #24 on: June 21, 2022, 03:28:41 PM »
Well, now I can invoke the power of weasel-words.  For you, "reasonable" means a longer nose that the shortest that you can possibly get it.   ;D
And I will counter with the son of Kodak.  My cell phone.  Long is in the eyes of the beholder and I beheld!

Ken
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Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #25 on: June 21, 2022, 03:41:20 PM »
I was suggesting putting the battery inboard or chin mounted because then the end of the battery can overlap with the motor.

But yes, CG is still an issue.  I've certainly seen a lot of planes that just notch the LE to get the battery back -- particularly older profiles with short-coupled tailfeathers.

I'm still wondering at your overall weight -- I'm not seeing how you need everything shoved that far back for balance unless the plane is as light as a feather.  Are you balancing the thing per the plans?
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Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #26 on: June 21, 2022, 03:52:10 PM »
Just to clarify, "inboard" meaning on the pilot side of the ( profile ) fuselage ?

Yes

What does this beast weigh without any of the electric stuff.?   I have seen some with the battery side mounted and angled with part of the battery over the wing.   I would do that before I shortened the nose to less than 7 1/2 inches.

Ken
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Re: Electric Banshee nose length and C of G position.
« Reply #27 on: June 21, 2022, 03:58:56 PM »
Here is a drawing showing the stock Banshee fuselage (top) and a modified Banshee with the wing moved forward 1.5" (bottom).   It will generally result in a much better flying airplane than the stock version.

Brodak's profile conversion package is inexpensive and include a cavity for the battery.  https://brodak.com/electric-accessories-1/conversion-kits/universal-d-electric-conversion-for-large-profile-models.html

The 3D Printed motor mounts from Okie Air are a very clever solution.  https://okieair.com/shop/ols/products/printed-motor-mount

Bob Hunt's HardNose method is very clean.  https://stunthanger.com/smf/gettin-all-amp'ed-up!/nose-construction-for-rd-1e/msg390207/#msg390207

Pat Johnston has a simple rear mount conversion package drawing you could copy. https://stunthanger.com/smf/gettin-all-amp'ed-up!/three-conversion-kits-for-profiles/msg476678/#msg476678

People have walked these paths before.  Step in their footprints if you need direction.
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Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #28 on: June 21, 2022, 06:50:19 PM »
Ok you guys have convinced me. I am going to abandon the ultra short nose ( it didn't look right anyway...) and go with a battery position over the wing and a more conventional nose length. I will finish off the airframe today and report back tomorrow with the a.u.w.

Thanks everyone !

( Yes Tim - balancing as per plans. )

Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #29 on: June 28, 2022, 05:46:01 AM »
It seems I have yet to learn how time-consuming some jobs can be. I guess it's to be expected as this is my first kit build (apart from a non-flaps model I made as a teenager back in the 70's, which I remember almost nothing of, only that it was a Mustang, O.S. 0.15 powered, had lots of spruce in it and I think was made in Japan. It also lasted a few laps, right up until I tried a loop... )

Working on the Banshee, it didn't help that I made several more errors, adding to the time to complete things e.g. Film covering the fuselage and having to drill the hole through the fuse for the landing gear wire legs, after I had glued in the wing. Made access difficult for both of these things. Also not having thought to pre-draw a temporary wing chord line, on the fuselage, before gluing in the wing. Again this was awkward to do afterwards but was needed to help position the motor mounts square to the fuselage.

Apologies for my late reply as my expected one day of work became more like one week.

Tim and Ken, answering your question, the weight of the Banshee without any power system components, is 22 oz but a tailskid and some way to retain the battery, esc and timer have yet to be added. I'm thinking maybe two ounces for these as I have some lightweight ideas in mind. I am waiting for new batteries to arrive ( any day now ) so cannot quite finish this off. Based on the previous advice I received, I now plan to mount the battery over the L.E. at an angle, hence I will be able to get the CG spot on ( to match that shown on the plans or else a little further forward. )

With the power system added, I am expecting the a.u.w. to be 42 to 43 oz ( that's with a 2650 mAh 4S battery ).

I am on the home stretch now.

Thank you again to everyone for steering me in the right direction.



« Last Edit: June 28, 2022, 07:01:42 AM by redout »

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #30 on: June 28, 2022, 07:32:20 AM »

.....hence I will be able to get the CG spot on ( to match that shown on the plans or else a little further forward.

Wow, getting there!

Go with the "little further forward".  2 reasons, first a slightly nose heavy attitude on the first flight is better than one that it too far aft and second, for whatever reason, electrics tend to want to fly better with the CG a bit forward.  Our technical experts here will tell you that it is .... just because.

It looks like it is time to "bench trim" before the 1st flight.  I will throw in my 2 favorites and leave the rest to the expert trimmers here.  First, controls neutral.  Make sure that the elevator and flaps are both dead level even at neutral and even with each other. Then work the controls both hard and soft and listen for any noise coming from the wing.  Stiff is not as bad as Clicks and squeaks.  Second add enough tip weight.  Add about 1/8 oz more than what the plans call for.  You can always take it out later but the one thing that will save your "a**" on the first flight if there is a warp or alignment issue is tip weight.  The first flight is an adventure, even for us old fart experts.  Keep it short.  Long enough to get a decent lap time and check the sensitivity of the controls, no maneuvering till you get it down, adjust whatever you find and thoroughly check it over for things that came lose, etc. 

On your next build, dial us up before you do the controls.  What you have is probably OK for now but as your skill progresses you are going to need stiffer and more reliable controls.

A quick note on batteries.  The need for anything over 2200mah is because of flight time.  The "pattern" dictates around 5:30 depending oh preferences.  If you are not doing the pattern a shorter run, say 5:00 and you can use a smaller battery.  Don't go under 4s though.

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Tim Wescott

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Re: Electric Banshee nose length and C of G position.
« Reply #31 on: June 28, 2022, 09:12:10 AM »
Ken probably considers it just part of building and not bench trimming -- but I'd include verifying that the plane is straight and true (everything square or parallel to the line of flight, no warps, etc.).

Then make sure that the controls are super free (also kind of a part of building) and that the CG is at a good starting point.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Online Ken Culbertson

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Re: Electric Banshee nose length and C of G position.
« Reply #32 on: June 28, 2022, 12:28:46 PM »
Ken probably considers it just part of building and not bench trimming -- but I'd include verifying that the plane is straight and true (everything square or parallel to the line of flight, no warps, etc.).

Then make sure that the controls are super free (also kind of a part of building) and that the CG is at a good starting point.
Actually I consider it both.  Alignment is something that has to be cared for from the start then rechecked when you are done.  Wood stress changes with sanding and things will move around if you let them.  I check alignment after every building session.  I think you said the Fuselage is MonoKoted.  If it is you are going to get wrinkles from time to time.  When you re-shrink them make sure that you have not introduced some warp or twist in the fuselage. Easy to do.

Good luck - when is the maiden flight?

Ken   

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If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline redout

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Re: Electric Banshee nose length and C of G position.
« Reply #33 on: June 28, 2022, 05:20:50 PM »
I will do all that's been suggested before I fly - good information.

I think the batteries will be delivered by next week at the latest ( they have to come by road ). First flight I expect shortly afterwards.

I did read somewhere that each plane should have it's own set of lines so I need to make up the connections on a new set. I also offset the lead-out ends a little on the Banshee so my other set of lines probably are not going to be usable anyway.

I am fairly confident I will maiden successfully, at least as far as having just enough piloting skills, as I inadvertently set the CG a little far back on an electric ARF Flite Streak I flew two years ago. Man, that was terrifying! But I hung onto it and kept it out of the ground. And at the end of the flight I even got a distant clap from an unseen observer. Couldn't believe how unstable that thing was !


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