[dirtdr]

I am planning to shave some weight off my 2.3m comp-arf Extra powered by a 3w-75

Right now she is sitting at 20.0lbs even.

Planned upgrades/modifications:
CF Wing and Stab Tube
Aeroworks ultralight tail wheel assembly
Ultralight wheels
Ignition Battery Delete
Pilot Delete
Wheel Pants Delete??
CF Spinner (will add weight as I currently have no spinner

I think this will add up to around a pound or so...
Any Ideas to shave more weight (without changing engine....yet)

[Tyler P]

Leave your pants on! lol. Seriously, Extras don't look good without pants. Even my Sukhoi looks way better now that I put the pants on it.

Does the plane have a canister or regular muffler? If you're on a canister, switch to a stock muffler. That'll save you a pound easy.

Another thought, what size is your gas tank and what kind are you using? I went from a 32oz Dubro on my 50cc to a 16oz Fiji water bottle. That saved a pound of fuel I wasn't using anyway, plus several ounces for the weight of the plastic. I can still fly a full 15 minutes on my 16oz with room to spare. You'll need a bit more, being on a 75cc, but switching to a juice or pop bottle of the appropriate size will definitely save some weight.

[dirtdr]

Thanks

I was thinking about the fuel tank as well. i always land with 2/3 full tank after 12 minute flight

I would like to leave the pants on, but they look soooooo heavy.... probably over half a pound between the two....
mabee i can just clean the dirt out of them to start with...hmmm

Motor is on a wrap-around.... hard to find other mufflers for this motor.

[Tyler P]

There's no way the pants are that heavy! lol. Maybe a couple ounces a piece, but I doubt much more than that! Leave 'em on!

Yeah, your muffler is probably as light as you're going to get, so no luck there.

The tank would be a great place to start. If you've got 2/3s of a tank after twelve minutes, you've got WAY too big a tank in there. I'm guessing here, but you could probably use a 20oz, or something along those lines for your 75. Depends on how you fly, though. In IMAC this weekend, I was flying two passes of the Sportsman sequence and only using about a 1/3 of a tank. In 3D I think I use even less, as I'm just floating around at half throttle most of the time.

The other CF options you're looking at are a good idea also. A bit pricey, but you can save a fair amount of weight with that change. The spinner won't add much. The heaviest part is the bolt that holds it on to the back plate. CF spinners weigh nothing. I've got a 4"or 4.5", I believe, for my Carden Yak build and it is insanely light.

Have fun! If you get the weight down, you're plane will feel like a new one.

[Oilsands]

Check out some fiberglass spinners by NoLimitz. They are light and don't have the carbon dust to worry about when cutting. You can get them through PAU (www.flypau.com)

[dirtdr]

i just picked up a new CF spinner from HiFlight store.

i dont know the make for sure, but is a more substantial CF spinner with CF backplate and it secures with a single center bolt.... much like true-turn aluminum ones.

total weight is 125grams with backplate, spinner, and bolt
and it come already precut

[Bryan Mailloux]

What is your electronics setup like?
There are many alternatives available today.
Lighter batts, wiring/ match boxes, switches. etc

[dirtdr]

electronics are pretty basic

spektrum ar7000 reciever
3200mah nimh 5 cell rec batt
hd switch/charge port
7955's all around w/4-40 hardware
pull-pull right off servo

ignition is to be replaced w/ ignition batt delete (Wike RC),so i will lose:
2400mah 4 cell nimh, switch, charge port, and rcexel opti-kill
this will be the single biggest weight loss item
http://www.troybuiltmodels.com/items/WRCIBEF.html

[mtr]

7955's can take 7.4v (Lipo) consider dropping Nimh Batt. Receiver will need to be able to handle 7.4v.

[dirtdr]

I thought it was only the HV servos that were good for 7.4v (7940HV - 7950HV)