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Old Feb 05, 2006, 02:34 PM
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Lizard's Avatar
Kemi, Finland
Joined Mar 2003
35 Posts
Question
4 Star 60 electric conversion

Hello!

Has anyone measured 4 star 60 how much does it weight without engine or without engine and radio equipment?

I am asking this because I am currently building 4 Star 60. I Started with wings. More time goes by more I would like to build this as electric model. The wings seem ok for me but fuselage seems way too heavy. If I know how much the plane weights normally without equiptments and motor, I could make decisions if my Flyware 350/25 is enough. I believe it would be easy to lighten the fuselage at least 25% or re-design it all over.

/ Jussi
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Old Feb 05, 2006, 06:10 PM
jollyroger
Central Lake, Mi.
Joined Nov 2002
1,025 Posts
Do a search for the plane. There are quite a few threads on this and the 4*40. One of the things most people do is shorten the wingspan by one bay on each wing.
I would also substitute the plywood fuse with a balsa one. Just trace out around the ply fuse sheets.
Also the plane does have an inherant weakness just behind the trailing edge, in the fuse. That area needs more reinforcement. Other than that it's agreat plane for conversion and many people ahve converted the "60" to electric.
Good luck with yours and keep us posted along with some pics. John Z
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Old Feb 05, 2006, 06:33 PM
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Lizard's Avatar
Kemi, Finland
Joined Mar 2003
35 Posts
Sure, I'll post pictures when I have something that differs from original 4*60. I hope the project to be ready for the summer. For me this is a long term project along with other interesting projects
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Old Feb 06, 2006, 02:27 PM
Registered User
Belfast / Dublin
Joined May 2004
1,554 Posts
The BTE e-friendly V60 which is the same plane just evolved a little further (same designer) does just that - substitutes balsa for ply in the fuse sides

lightening holes all round should help matters too as well as a lighter covering material

I don't see why a flying weight of 5ish lbs can't be achieved... certainly under 6

a 235 to 250g outrunner motor should be plenty... such as the Cyclon 60, Kontronik Kora 25 or Plettenberg Orbit 25

big bird
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Old Feb 07, 2006, 02:29 PM
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Lizard's Avatar
Kemi, Finland
Joined Mar 2003
35 Posts
I have been looking the BTE Venture 60 earlier, but I happened to bargain 4*60 real cheap. I think that the changes I will do to will change it's outlook closer to the ventyre 60.

Today I was building fuselage. I will build it from the original plywood, but i didn't use the doublers. I think those are extra weight for the electric model. Those are needed, if your IC engine is shaking the fuselage. The doublers are also needed for IC-engine start, where you need some extra fuselage strength.

The horizontal plywood part under turtle deck was cut away. It was used only for alinging fuselage straight while gluing.

The firewall, and the nose will be redesigned lighter and more aerodynamic.

The weight sawing so far has been around 100g.
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Old Feb 07, 2006, 06:24 PM
Registered User
Belfast / Dublin
Joined May 2004
1,554 Posts
sounds good... a lot of the mass needed to absorb the shaking of a 2 or 4 stroke glow engine simply isn't needed in the electrics - so quite a bit of weight can be saved here.

the ribs can get lightening holes too and maybe stick build the tail feathers?

keep us posted, this will be an interesting build

big bird
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Old Feb 07, 2006, 09:11 PM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
12,788 Posts
The Four Star 60 wasn't so much designed by Bruce Tharpe as extrapolated from his 4*40 and 4*120. Somehow, like many committee decisions, it got very weighty in the process.

On my now nearly six year old 4*, I cut down the fus doublers to make little more than ledges for the battery tray and a locator for a 1/8" firewall from one of two laminations in the kit version. I also lost the liteply fuselage bottom aft of the wing. The 4*40 wings are fine as is, though I'd make them much lighter if I ever built another.

The E-V60 is a way better machine all round - for one, the electrics fit is fully drawn out on the plan (I know, I did it for Bruce ), plus the model's design cures a lot of the handling funnies of the Four Star - which wasn't really an all-out pattern bird to start with, more a "first low winger" follow on to the hordes of Kadets.

The Liteply UC fix on the 4*40 was somewhat inadequate - kept ending up landing rollouts with the model and its gear in different locations. The UC is a bit short if you start using geared drives - I had to use an after-market as the kit gear would only clear 11" and sagged on the bench with a battery on board!

Lop a bay off each tip - these things will float the length of the national mall if you come in a little hot. Taking a bay off allows for a decent descent rate, ups the roll and snap rates and doesn't hurt the low speed handling at all.

Never met anyone who didn't like their 4* - that says a lot

Dereck
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Old Feb 08, 2006, 12:36 AM
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Lizard's Avatar
Kemi, Finland
Joined Mar 2003
35 Posts
Thanks big bird and Derec for your comments. It seems there are quite many 4* lovers besides me. I also have fell in love with it's flight characteristics. Originally I borrowed my friend's 4*40 for tens of flights. Maybe my total number of flights with that 4*40 are close to 100.

The Balsa quality of the kit seems very good, but the laser cutting just doesn't match my plans! The building plans are clear but it doesn't help, because I am doing alot changes. The packing and overall looks of kit is also very good expect the cabin, which had a small blem. Maybe I will give only 4* out of five about the kit quality for this 4*60
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Old Feb 09, 2006, 05:35 AM
jollyroger
Central Lake, Mi.
Joined Nov 2002
1,025 Posts
4*60

Lizard, sound like you've got a handle on it. Good idea about the hatch.
I built the "60" and dressed it out in German Luftwafe livery. Somewhere I've got some pics. Put a lot of money in extras ie. scale tires, pilot, etc. used Monocrap flat O.D.....was the worst covering I have ever used. After airbrushing Luftwafe camo and adding the bumps(intake scoops) new canopy and all the markings it looked pretty good for a fun stand way off scale. It was a lot of fun to do, but was difficult to maintain eye/ hand contact against a background of trees.
I want to build the "40" next for electric as I already have a Goldberg Tiger 2.
There a several other "60s" in the club and everybody loves em.
Dereck, I didn't realize BTE made an E version of the "V-60". Sounds like something I might want to investigate.
How about some pics Liz.?
John Z
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Old Feb 09, 2006, 03:10 PM
Aviator
Lizard's Avatar
Kemi, Finland
Joined Mar 2003
35 Posts
Quote:
Originally Posted by John Z
I built the "60" and dressed it out in German Luftwafe livery.

How about some pics Liz.?
My friend had a 4*40 coloured in WW2 russian fighter colours with the red stars It was very nice looking ww2 "scale" fighter

You are right about the pics. Those are more interesting than just text.

On the first picture you see black arrows on the nose. This is where I am going to cut the cheeks and build more aerodynamic cowling. The red arrow points the place, where I cut the horizontal plywood off. I decided to keep it over the wing for stuctural strength and it would be nice floor for a big battery pack. The top of the nose will be build higher a bit for accomodating battery and it can be taken off for easy acces to batteries. This placing allows easy moving forward and backward for the pack for placing CG (and during a crash the pack wouldn't crash my ESC and motor ) The green arrow points to the place, where doublers would start (if used).

One must eat to become big. On the second picture you can see that the fourstar ate my speed400 class pylon Stinger

The third picture is about the elevator. It is a bit heavy because it was build earlier .90 Super Tigre engine in the mind. Now those seem too heavy. Those weight about 118g and it would be easy to save 30% from it. I'll build lighter ones later, if I'm feeling enough energetical - this elevator would be built all ready you know

The wings were build allready and those contain nothing special. No bays have been cut off. I have 4 servo configuration in my mind for the wing. This is because I love flaps Flaps also helps to slow down for the landing with 32 cell battery pack. This configuration gives me 1500W. Yes, I will buy LiPo-pack later but first I will build the plane
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Old Feb 09, 2006, 04:57 PM
Registered User
Belfast / Dublin
Joined May 2004
1,554 Posts
looking good... but that stab and elevator looks like a right vulgar plank of wood ... stick building that would save you quite a bit in weight and help off set the balance issues you may have when you put a comparatively light e-motor in the nose - typically they weigh half of their glow motor equivalent

saito 82 with muffler approx 520g (maybe more) ... cyclon 60 is 235g, Hyperion 4020 is 285g

cells and ESC will take up some but perhaps not all of the slack...so be prepared to make a light tail

big bird
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Old Feb 09, 2006, 05:00 PM
89" Kool Aid drinker.
Smash McCrash's Avatar
United States, CA, Ventura
Joined Dec 2001
3,133 Posts
John, the E-V-60 is a first come first served offering from Bruce. I have one sitting on a shelf waiting for its turn. I alredy have all of the parts for it, just need time to build the airframe.

Liz: Looking good so far. I was wondering what those big green things were in the pictures. :P

Mike
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Old Feb 09, 2006, 05:04 PM
Registered User
Belfast / Dublin
Joined May 2004
1,554 Posts
yeah, the e-V60's are not always available ...they're done as an adjunct to a run of conventional V60's - which are done periodically, but are also not always available... so it's a matter of contactin Bruce Tharpe, or checking the website regularly if you want one

big bird
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Old Aug 07, 2006, 11:05 PM
Fly it like you stole it..
Tram's Avatar
Florence, Al
Joined Oct 2000
29,298 Posts
Just sent Bruce an e-mail on the Ev60
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