Weight for Ripmax AcroWot MK2 Balsa ARTF?

[Scruffmeister]

If you have a Ripmax AcroWot MK2 Balsa ARTF how much does it weigh with your setup?

Including servos/Rx, Saito 82B + muffler and 380cc World Models fuel tank and aluminium spinner mine weighs a total of 4.5Kg (158 Oz) dry incl. a small amount of lead at the rear to make to CoG.

This seems a little heavy as I'm sure I've heard reports of kit built AcroWots weighing nearer 6 lb?

Weight is divided between the wing at 1.75Kg (61 Oz) and the Airframe at 2.75Kg (97 Oz).

Maybe I should re-measure, but I'd like to see data from other models. I'm thinking of electrifying it, but at that weight I think we're looking at a 6S setup delivering 1300W to give 120W/lb... seems excessive!!?

Edited By Scruffmeister on 26/12/2013 14:47:42

[Dave Miller]

It's certainly a lump, mine weighed a similar amount with an OS 72 and 6oz of nose weight. It was not a pleasent model to fly, unlike the kit built version.

I scrapped it after it fell out of the sky and build a Gangster 63 which, at a little over half the weight of the Ripmax lump, was a pleasure to fly on an OS56 4stroke; I have now converted the Gangster to electric.

I remember building Acro Wots in years con by and being miffed if they went past the 5lb mark with a four stroke up front..

[kc]

I can hardly believe the weights quoted! Presumably the ARTF Acrowots are the same size as the 58 inch kit built models?
Just weighed my old, well flown, oil soaked, kit built Acrowot and it is 2.49kilos exactly as flown. Fuselage with Enya 40SS and 3 servos etc is 1.895 kilos and the wing with 1 standard servo is 0.595 kilos. Total 2.49k for a film covered model with lots of decals.
Another spare wing is 0.625 kilo with servo it's tissue covered and brush painted with Japlac.
Just swapping my wing for yours would save well over a kilo!
I am pretty confident my scales are fairly accurate.
Are you sure your scales are OK?
At nearly 2.5 kilos my Acrowot is well overweight and does not fly particularly well for that reason.

Better not to waste time electrifying an overweight model in my opinion.

Edited By kc on 26/12/2013 16:50:41

[Dave Miller]

I've just been out to my workshop and weighed mine. The ARTF Ripmax AcroWot airframe without engine or radio gear weighs:

Fuselage 1248g and the wing 610g = total 1858g to which must be added the weight of and engine, prop, spinner and radio equipment and about 170 g of lead nose weight if fitting an OS 72 four stroke plus fuel.

On the other hand (as a comparison) my Mick Reeves 63 inch wing span electrified Gangster now weighs:

Fuselage 958g with motor, spinner, prop and radio. The wing, complete with 2 standard servos weighs 595g. To this must be added a battery which is a 4S 3700mAh and weighs 409g. So the flying weight is 1962g or a bit under 41/2 lbs in old English.

Edited By Dave Miller on 26/12/2013 17:05:41

[Scruffmeister]

I re-weighed the model - and found that the Silverline hanging scale I used is rather inaccurate! Here's the re-weigh of the mechanical scale vs the digital kitchen scales. I'm assuming here that the digital kitchen scales are the "correct" ones, especially as they tally with Dave's measurements above.

Fuselage: 3.125Kg (Silverline), 2.12Kg (Digital)

Wing: 1.350Kg (Silverline), 0.74Kg (Digital).

Allowing about 0.380Kg for a full fuel tank, we have a flying weight of 3.24Kg which seems a lot more reasonable What is it they say, check, check and check again!?

[Dave Miller]

Scales can be checked with something unopened from the kitchen cupboard as most consumables have an accurate weight marked on them.

[Scruffmeister]

I checked the digital scales by zeroing them with an empty jug on, then adding exactly 500ml of water to the jug. Reading was almost exactly 500g so I'm happy enough they're accurate

Edited By Scruffmeister on 27/12/2013 08:57:57

[Dave Miller]

I have prepared an album of the motor installation in my Gangster rather than posting it here as this thread is really about the AcroWot ARTF lump.

[Levanter]

Dave. Careful with the stuff from the kitchen. Most things are Net Weight ie excluding the packaging. Scruffmeister's plan is better although ignoring the temperature constant!! Accurate enough for us.

[Dave Miller]

Posted by Levanter3 on 27/12/2013 10:57:28:

Dave. Careful with the stuff from the kitchen. Most things are Net Weight ie excluding the packaging. Scruffmeister's plan is better although ignoring the temperature constant!! Accurate enough for us.

Good point so scrub my idea. I must admit that I have a set of laboratory standard brass check weights that I use.

[Scruffmeister]

Dave, thanks for the album on the Gangster. Really helpful to see! Has it flown yet?

[kc]

That's a much better weight now! I was fairly confident my digital scales were near accurate as they were also compared to digital luggage scles which had been tested by the Essex Weights & Measures Dept. Of course kitchen scales need to be put on a level surface and even moving the plane around on the platform can produce varying readings. Luggage scales work by suspending the weightso thats better. If you travel by air then digital luggage scales will save their cost!
But that Acrowot is still very heavy.
My used, oilsoaked kit built fuselage weighed 0.96 kilo and the used wing 0.55 kilo. Total 1.51 kilo without radio,servos, nicad or engine but otherwise as flown ( as acquired secondhand from a clubmate)

So about 2.5 kilos complete or 1.5 kilos bare is fair for a well used example, but almost half a kilo more than one I built from scratch.