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Old Dec 30, 2012, 05:05 AM
Another one on the way...
ysolomon's Avatar
Plano, Texas
Joined Feb 2009
2,390 Posts
Wow! This thread has been "dead" for the last 6 months, and yesterday, just as I started planning the continuation of the build--three posts... I was going to go with MAS 16x10x3 props. I have two of them. But I also bought two Zinger 18x12x2 props, so we'll see. In both cases, I have (and will be using) one "regular" and one "counter rotating (pusher)" prop (remember that I have an electric setup, so I have the ability to decide that one of the motors will go in reverse. If I loose one in the air, I don't have a "critical engine" problem this way. Both props will turn TOWARDS the fuselage (the prop top turns towards the fuse). To address the concern of the counter rotating prop nut getting loose I will be drilling two holes through the prop and the prop shaft base and put thin pins through them.
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Old Dec 30, 2012, 10:25 AM
Dont be divided from the truth
Dangaras's Avatar
Canada, ON, Toronto
Joined Mar 2010
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Quote:
Originally Posted by ysolomon View Post
Wow! This thread has been "dead" for the last 6 months, and yesterday, just as I started planning the continuation of the build--three posts... I was going to go with MAS 16x10x3 props. I have two of them. But I also bought two Zinger 18x12x2 props, so we'll see. In both cases, I have (and will be using) one "regular" and one "counter rotating (pusher)" prop (remember that I have an electric setup, so I have the ability to decide that one of the motors will go in reverse. If I loose one in the air, I don't have a "critical engine" problem this way. Both props will turn TOWARDS the fuselage (the prop top turns towards the fuse). To address the concern of the counter rotating prop nut getting loose I will be drilling two holes through the prop and the prop shaft base and put thin pins through them.
All you need are anti-vibration washers, the ones with the teeth on the inside, between the prop clamp washer and the prop nut. This is how I secure the props on my big A-26.
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Old Dec 31, 2012, 07:59 AM
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tone_tbm's Avatar
Joined Jan 2009
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Originally Posted by morganew View Post
Anyone have experience with the v3 units? Is there an upgrade kit from v2?
There are upgrade kits but the first batch sold out immediately. If you have version 2, please contact us for replacement.

ESM & ECOM RC V3 Retracts First Look (0 min 28 sec)
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Old Jan 07, 2013, 04:03 PM
Dont be divided from the truth
Dangaras's Avatar
Canada, ON, Toronto
Joined Mar 2010
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I was planing on starting with Tacon 160s & MA 16*10*3. Does anyone have any current data? I still need to size my ESCs and batteries.

I could simply get a couple of HV 100A ESCs and start with two 6 cell, 5000, 25C batteries in parallel then go up to 2 x 8 cell if necessary...

Any existing data would be nice before I head off to e-calc..
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Old Jan 07, 2013, 04:49 PM
Another one on the way...
ysolomon's Avatar
Plano, Texas
Joined Feb 2009
2,390 Posts
Dangaras, take whatever I tell you now with a grain of salt, as I haven't finished the build the don't have numbers. My setup is Tacon 160 with HobbyWing 120A HV ESC. Note that the Tacon 160 is rated up to 14S LiPo. You appear to want to drive them by 6S/8S? The motor has 245Kv. If you run it at 6S, you will get only 5400 RPM. I think that even on a 160x10x3 prop you will not get anywhere near the amount of power you need for this plane. On 8S, you will get 7300 RPM max. For a 16" prop, you probably need around 9000 RPM (the rule of thumb is 160,000 / diameter in inches, so 10,000 for this prop. I'm planning on using 12S batteries (2x 6S 5000mAh in SERIES).

One question to think about, though, is where you want to put the ESCs. I initially thought about putting them in the nacelles, but then realized that I will have very long battery leads. Maybe OK with capacitors all the way, but I don't like it. Now I'm thinking about putting them right on the center wing (under the canopy), or maybe even in the nose (close to the batteries), and run long motor wires instead.
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Old Jan 07, 2013, 05:07 PM
Dont be divided from the truth
Dangaras's Avatar
Canada, ON, Toronto
Joined Mar 2010
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Ah yes. Forgot about the KV rating.... Well that will be interesting to say the least.

I will probably end up working the values with ecalc. I want to use te batteries I already have. Maybe the 2 x 6 cell in series paralleled might be the answer.

I keep my ESCs in the airflow as close to my motors as possible, better to keep them cool. I already fly a few twins (some large) with long battery leads and I have no issues, never have.

I tested a NTM 50-65 320kv with a 2 blade 18*10 & 6 cell battery. I got 60 amps, about 1400W so I was suspicious about my current plans.....

Anyway, I will post what ecalc has to say.
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Old Jan 07, 2013, 10:46 PM
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Canada, ON, Owen Sound
Joined Oct 2008
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Hi Dangaras: My testing on 16/10/3 and 16/12/3 blade props show that on 6s the seemingly ideal place is 320 kv.
My results show an SK3 5055-320 pulling 48A for 1100watts. Taking that number it means at 22v under load the prop will spin approx 7040rpm for about 61 mph with the 16/10/3.
The 16/12/3 shows 54A for 1245watts, prop speed a little less, but airspeed up to 70 mph.
Your motor will require at least 8s or maybe 10s to achieve the same numbers. Likely 10s.
Creg Covey flys his Tigercat on 10s, with Eflite 160's, I've seen it fly, it rocks!! Doug B
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Last edited by Doug Bartley; Jan 07, 2013 at 10:48 PM. Reason: add
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Old Jan 08, 2013, 08:10 AM
Another one on the way...
ysolomon's Avatar
Plano, Texas
Joined Feb 2009
2,390 Posts
Quote:
Originally Posted by Dangaras View Post
All you need are anti-vibration washers, the ones with the teeth on the inside, between the prop clamp washer and the prop nut. This is how I secure the props on my big A-26.
Sounds like a good idea. I'm also thinking about drilling two small holder through the prop and into the shaft backplate and insert pins there.
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Old Jan 08, 2013, 08:15 AM
Another one on the way...
ysolomon's Avatar
Plano, Texas
Joined Feb 2009
2,390 Posts
Quote:
Originally Posted by Doug Bartley View Post
Hi Dangaras: My testing on 16/10/3 and 16/12/3 blade props show that on 6s the seemingly ideal place is 320 kv.
My results show an SK3 5055-320 pulling 48A for 1100watts. Taking that number it means at 22v under load the prop will spin approx 7040rpm for about 61 mph with the 16/10/3.
The 16/12/3 shows 54A for 1245watts, prop speed a little less, but airspeed up to 70 mph.
Your motor will require at least 8s or maybe 10s to achieve the same numbers. Likely 10s.
Creg Covey flys his Tigercat on 10s, with Eflite 160's, I've seen it fly, it rocks!! Doug B
I would worry about having a maximum speed of 60-70mph. I don't believe this plane will remain airborne under 40mph... I would want to get at least 2000-2200W per side, so I'm going with 18x12x2 and 12S. Again, this is my PLAN, I don't have any numbers yet. What I do know is that I have a RIMFIRE 1.60 on my CMP P-40E (73", 16lb), and when I flew it on 10S 5000mAh and 16x10x3, I downloaded the log (CC 120HV) and saw that while on the ground I was getting a nice 2500W--in the air, even at full throttle, I got 1300W... That plane seemed very slow in the air.
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Old Jan 08, 2013, 08:31 AM
Dont be divided from the truth
Dangaras's Avatar
Canada, ON, Toronto
Joined Mar 2010
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This beast is going to weigh 30lb AUW and futzing with battery size will only add to the weight.

I want to aim for 130W/lb. This model will need to fly to stay in the air, no leaf on the wind nonsense.

I use 50-55s in other models but my calculatios tell me they wont give me the power this model needs.

My A-26 weighs 16lb, 92 in WS flies on Aolean 42-60-600kv, MA 13*8*3, Turnigy 80a plush & 5cell, 4000, 25C *2 in parallel. I have power to spare and she screams past on a low level fly by..
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Old Jan 08, 2013, 08:52 AM
Another one on the way...
ysolomon's Avatar
Plano, Texas
Joined Feb 2009
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30 x 130 = 3900W. I rest my case... My plan is not that different than yours. 130-150W/lb. Now, I haven't finished building her, and I can already tell that the mounted motors do add some weight forward of the CG, but my guess is that it will still take a lot of weight in the nose just to balance this looooong tail. Might as well be batteries... I do not want to add any dead weight. Weight management will be the trick here.
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Old Jan 08, 2013, 09:18 AM
Dont be divided from the truth
Dangaras's Avatar
Canada, ON, Toronto
Joined Mar 2010
3,286 Posts
I agree. That power level is perfect! Oh yes, the loooong tail will definitely need some nose weight. Same as my A-26....
She should arrive today, I will do an inspection then put her away until later in the year. Definitely will be following your lead.
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Old Jan 08, 2013, 04:39 PM
Another one on the way...
ysolomon's Avatar
Plano, Texas
Joined Feb 2009
2,390 Posts
I have a couple of planes I'm working on in parallel (an A-RC F-18 and E-Flite Habu 32 which I just completed and should get off the workbench, and a Fly-Fly L-39 I'm glassing), but I want to find time and bring the F7F back to the workbench as well.
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Old Jan 08, 2013, 07:53 PM
Another one on the way...
ysolomon's Avatar
Plano, Texas
Joined Feb 2009
2,390 Posts
Meanwhile... I just purchased the V3 electric retracts from TBM. Now I have both the air system (it was $169, if I'm not mistaken) and the electric one ($319). Including the struts--those are great prices! So, I can consider this as having TWO sets of struts. I just don't want to mess with the air system on this plane. I don't have brakes, and even if I add them later--it's OK to have the air system only for brakes. They are just too problematic for the retracts themselves.
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Old Jan 08, 2013, 08:03 PM
Dont be divided from the truth
Dangaras's Avatar
Canada, ON, Toronto
Joined Mar 2010
3,286 Posts
I have a set of spring-air retracts and they are pretty reliable. The only issue is the NOT scale performance. The oleo-struts are good but the nose strut can bend when I am flying off our bumpy field.

I tried some RCLander e-tracts on my A-26 but again they are unreliable on our bumpy field. Actually bent the tabs on the push bar.

I have the ESM V3 e-tracts as well. Waiting for them to arrive.
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