mrc100

My Feedback: (4)

What's the best source for titanium bolts for axles and engine mounting? I need M6x70mm and M6x30mm.

My yak is going on a diet.

mrbigg

My Feedback: (21)

I'd do a search on the web. Not worth the extra cash for the little return you'll get, in my opnion. If that's a CARF, they fly light anyway. Your money though.

Jake Ruddy

My Feedback: (40)

If you had a plane that had bolts for control horns as well and did all control surfaces and engine bolts you might save 2 or 3 oz for the $75-100 expense. Most have thought of this and backed away from it.

There are better ways to save weight. Switch to a water bottle for a fuel tank, that will save 3-5 oz depending on the size of your tank and cost less than $20 with the stopper and everything.

jon595

My Feedback: (2)

For that same amount of money you can buy a carbon wing tube a save 8 oz. I'm finishing up mine now and have not had a chance to see what the AUW is.

mrc100

My Feedback: (4)

Thanks for the suggestions and opinions.

This is what I'm thinking at this point.

Scrap the titanium idea
replace stock tube w/ carbon fiber wing tube
Replace DuBro 5" tires w/ kavana tires
I have some plywood for ducting that I'll replace with some balsa
replace steel engine mounting washers with alluminum offsets - to both move the engine forward a bit for better cg placement and reduce weight a bit
go from 1/2" foam to 1/4"

I'm a bit torn with the idea of spending $$ to replace my two receiver NiMh 2150mAh 6.v batteries with Lithium+regulators. If I'm right I have figured a regulator + similar sized Li battery will run about 6oz which is the weight of my current NiMh. Any advise or education for me? BTW - I'm using a Fromeco Wolverine switch which accomodates two batteries.

mrc100

My Feedback: (4)

forgot to add one other idea.

replace my PT carbon fiber prop for a wood NX for 3D flying...not sure what that will save...probably a couple oz.

Tired Old Man

My Feedback: (1)

Since mine had reached the 2 year mark I removed my pair of 5,200 Mah li-ons and regulators and replaced them with a pair of 2,300 mAh A-123 batteries. Had to change the switches as well but a lot of wiring dissapeared in the process. Changed out the ignition battery and regulator to a 2,000 mAh Eneloop AA nimh. There was a noticible weight loss after removing all the associated li-on stuff. Much simpler wiring to boot.

The Kavan tires are a bit squishy so if you're running the Compy wheel spats and mounted low you might want to watch out for the possibility of grinding the spats away on every landing.

A Yak is scale in appearance without a spinner so you have an option there. I've weighed a few wood and carbon props in the needed size range and the carbons are a lot heavier.

I have both the stock and carbon wing tubes and haven't determined if there's all that much of a weight difference between them. Enough to justify the cost of carbon is argueable.

Tired Old Man

My Feedback: (1)

Forgot to note.

If you're really into spending money to shed weight get a BME 116 and save pounds You'll have to move some things around inside to compensate though....

Jake Ruddy

My Feedback: (40)

I don't want to nit pic.. but considering A123s weigh 6oz a pack I don't see how you can save that much weight with 2 of them in there compared to another solution.

If you want to get crazy run 2 1100 A123s, get rid of your ignition battery and run it from the A123s. Thats 6oz total in batteries. Just be prepared to charge every 3-4 flights.

Tired Old Man

My Feedback: (1)

I still use a 72 mhz radio and won't risk potential rfi feedback from an ignition system to the receiver. For those using 2.4 it works but I don't want to chance a $4,500.00 loss to something easily avoided. You're not nit picking at all. Good point.

I had a pair of 5,200 ma Lions and a 2,600 ma ignition li-on in it. Those, combined with their regulators and associated wiring, come out a bit heavier than the 2,300 A 123's and the 4AA cell Eneloop with their switches. Not a big difference, but noticable side by side. What is very nice was the amount of wires eliminated in the switch.

I'm staying with a pair of the larger A-123's because with the exception of the elevators every surface has a pair of 8611's driving them. So there's 8-8611's and a 4721 pushing things around. Lots of amps with the A-123's and plenty of stored supply with the 2,300's.

jon595

My Feedback: (2)

The stock wing tube is suppose to weigh 14 oz. Mine is very heavy so I'm spending the extra money for a carbon tube. Using 2 2300ma A123 packs into an AR9100 Powersafe Rx (just the 1 little switch and no regs). Have unregulated li ion for ignition (3W 110 on cans). 8611As on everything except throttle, 8417 for that. I am using the cheap Chief Aircraft 5" wheels. These are the biggest wheels I have ever had on a plane and they seem ok. Ordered a plain white plane and had Kirby's make some graphics for it. The only thing extra I added was making the fuel tank tray removable and replaced the pushrods and associated hardware. Most of the pics I have seen show unbaffled engines. So for now the baffles are being left out. Please excuse the crappy cell phone pic.

Tired Old Man

My Feedback: (1)

The removable tank mount was a very good idea. Makes access to stuff up front, which is a lot of stuff, a lot easier later.

Mokken

My Feedback: (63)

Guys, don't take this the wrong way. But don't be so obsessive on the weight of this plane. I've owned the same 2.6m YAK now for 5 years. Did the removable tank deal, why they would want you to permanently mount that try is beyond me.

I was running all duralites, they have since bit the dust and have just replaced them all, including ignition battery with 2300mah A123 packs, still running duralite 6v regs on the RX and 5v on ignition.

Don't worry about light wheels, titanium bolts, axles, nuts. The stock wing tube is solid, why change it? I used all the stock hardware except for Airwild uni-arms in the stock rudder location and have all SWB double lock servo arms. The Kavan wheels are terrible, unless you get the hub replaced, PSP MFG, sells a nice CNC machined hub for those wheels, I have 5" sulivan skylites with alum hub, held up great.

I can't tell you how light this plane flies and it weighs 27lbs. The only thing I plan to change are the servos, right now I'm running 5945's, they have been great, but are long in the tooth.

I realize I'm nobody in your little circle, I just wanted to tell you from years of experience flying this plane, that weight will "not" be an issue, your flying skills will be. There is nothing you can't do with this plane, short of your skill level. It's the best and I mean best flying aerobatic airplane I've ever flown or owned.

mrc100

My Feedback: (4)

i've had mine for roughly 3 years and built it totally stock. However, where I live noise is an issue so I have KS tuned pipes that add a bit of weight. Most everyone else I see with this plane doing 3d have in cowl mufflers. Wing rock in an upright harrier is pretty busy so I believe trimming a pound + will settle it down. I'll report back on the difference.