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Old Oct 31, 2011, 04:46 PM
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Toronto Canada
Joined Aug 2004
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Question
ESM/KMP Typhoon/Hurricane nose weight?

Guys,

I've been thinking of picking up either a ESM Typhoon or ESM Hurricane for "electrification" for a couple of reasons. One ... I really like the look of them and I hear good things about their flying chracteristics ... and two I hear they need a substantial amout of nose weight to make the CG.

The reason that I'm thinking the latter might be a plus in my case is that I have a really HEAVY honker of a motor that's looking for a good home! So I figure that I might be able to put this weight to good use.

So ... my question to all the guys who have converted these planes and know exactly what it takes to balance them is this:

Can my 42oz motor and 60oz battery pack enable me to get away WITHOUT having to add extra "deadweight" in order to meet the CG?

I've heard of people having to house the batteries in the cowl (eg:Typhoon), adding heavy prop nuts etc etc to balance these babies but I would prefer not to have to do that in my case.

Preferably I would like to be able to house my packs behind the firewall (as is common in a typical conversion) and add your typical "top hatch" for battery access etc.

Can I achieve my goal with these planes using my heavy "bits"?

Colin
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Old Oct 31, 2011, 08:45 PM
Registered User
Leduc, AB, Canada
Joined Oct 2008
562 Posts
Hi Colin,

I'm thinking with 6.8lbs up in the nose, you should do ok or at worst require only a small amount of ballast to reach proper CG on the Typhoon with your setup.

Mine is 99% completed and currently weighs in at 18.2lbs with 5.7lbs of motor, ESC, and batteries up front. However, with the landing gear up, the plane's CG is at 111mm (100mm is the manufacturer's CG) so I figure I still need about 15oz to get it on the money.

Keep in mind, my Typhoon has been heavily modified with retracable tailwheel, scall resin parts, cockpit, cannons, etc. It also has the fiberglass wing so it weighs a little more and in different areas than the stock Typhoon.

As for the Hurricane, I haven't started on that project yet (planning this winter) so I have no idea if your setup would balance that model. If you plan on building the Hurricane, keep me posted on how it works out for you.

Cheers,
Peter
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Old Oct 31, 2011, 10:11 PM
"RC ADDICT" in Toronto!
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Toronto Canada
Joined Aug 2004
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Originally Posted by Orvis View Post
Hi Colin,

I'm thinking with 6.8lbs up in the nose, you should do ok .

So this requires almost seven pounds in the nose to balance?! Holy crap! I was hoping to get away with NOT having my packs in the cowl. My main concern with this (besides the awkward accessibility) is that it's a lot of weight for a cowl to handle, no?

I have no experience whatsoever with ESM planes (never even seen on in the flesh) so are their cowls attached to their fuses any differently from other brands? I can't imagine putting almost four pounds of batteries in a "regular" plane's cowl being that they're typically only attached by a few little screws! Also the typical plane's cowl tends not to be the most robust of parts, hence my concern.

I'm actually subscribed to your thread and think you're doing an awesome job! Are there any other threads with conversions of these planes? I can't seem to find any others ... Can't believe more people aren't converting these ESM warbirds cause they look awersome.

Thanks again for the response, Peter!

Colin
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Old Oct 31, 2011, 10:29 PM
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Leduc, AB, Canada
Joined Oct 2008
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Colin,

The ESM cowls attach to the fuselage the same way as any other model; with screws. I have learned in my build you do not have your battery tray on the cowl itself. You are right, it will not hold up without reinforcement.
I have attached my battery tray to the firewall inside the cowl and cut a hatch in the bottom of the cowl.
There have been quite a few electric conversions, but very few documenting their builds, hence the lack of info.

I think with your power setup weight you should be ok so long as you keep the batteries on or forward of the CG. For instance, were the fuel tank would go.

Cheers,
Peter
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Old Nov 03, 2011, 02:56 PM
Rangers Lead the Way
Joined Mar 2010
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I would definitely plan to locate the batteries in the cowl. I have the Spitfire and face the same problem. Also, be advised that published CG on some or all the ESM/KMP planes may be wrong, resulting in a tail heavy plane. Best to verify CG at 25% MAC for the first flights.
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Old Nov 03, 2011, 05:53 PM
Bypass Ratio = Infinity
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United States, NC, Jacksonville
Joined Apr 2006
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Quote:
Originally Posted by TTRotary View Post
I would definitely plan to locate the batteries in the cowl. I have the Spitfire and face the same problem. Also, be advised that published CG on some or all the ESM/KMP planes may be wrong, resulting in a tail heavy plane. Best to verify CG at 25% MAC for the first flights.
How does the CG on the Spitfire differ from the plans?
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Old Nov 03, 2011, 06:06 PM
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Leduc, AB, Canada
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The manufacturer's CG for the Hawker Typhoon is accurate at 100mm; you just have to keep in mind it is measured at the outer wing joints instead of inboard at the root as most models are measured.


Cheers,
Peter
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Old Nov 03, 2011, 06:34 PM
Rangers Lead the Way
Joined Mar 2010
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If I recall, others wound up 1-1.5in forward of where the manual stated. I believe the issue was that the published CG was erroneously carried over from the larger model. I clearly remember that it was recommended to calculate 25% MAC at the fuse and use that as a safe starting point. Seems to be the rule for most of these warbirds. I don't know why the manufacturers get this wrong so often. Planned "obsolescence", perhaps?

I have not built the plane yet, so I have no real world info.
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