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Old Oct 18, 2010, 09:47 PM
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Is there any disadvantage to losing the rubber tip of the prop on the stock prop? I think mine is about to come off cause I inverted stalled at like 8 feet up and hit the dirt hard.
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Old Oct 18, 2010, 09:50 PM
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Southlake, TX
Joined Jan 2008
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Originally Posted by iceman88 View Post
Is there any disadvantage to losing the rubber tip of the prop on the stock prop? I think mine is about to come off cause I inverted stalled at like 8 feet up and hit the dirt hard.
It saves knocking the gearbox lose when you run the plane into stuff.
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Old Oct 18, 2010, 09:54 PM
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Canada, MB, Winnipeg
Joined May 2010
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Originally Posted by CNY_Dave View Post
If the controls go to neutral and the red led in the cowl goes out, its likely a tx problem (or maybe an esc RF noise issue?).

Dave
I did have it need re-binding the other day to my DX6i.

However, the controls stay in their assigned positions, as I have seen the plane "pulse" during turns, on occasion, with no apparent interruptions to the controls.

SC
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Old Oct 18, 2010, 10:45 PM
Static Model Collector LOL
Katy, TX
Joined Dec 2009
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Originally Posted by Doug Sipprell View Post
I usually get 14 - 16 minutes, but have gotten as much as 20. I don't fly close to the ground, making circles, etc. I fly at higher altitudes, with some closer to the ground buzzing. A hand full of inside loops, wing overs, hand launched. 240 cell works great. I don't use the 160's any more, strictly 240's. Hyperions's are the one's to use, forget about the HK Zippies. Very slight modification to the battery tray to get the 240 cell to fit. Try it, you'll like it!!


RD
Just ordered some 240 mah Hyperions from RCBABBLE
and some GWS 5045 props, and prop inserts from Radical RC

Time to have some fun with the CHAMP

Thanks for the advice everyone, been asking a lot of questions

FCA
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Old Oct 18, 2010, 10:46 PM
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Originally Posted by UNGN View Post
It saves knocking the gearbox lose when you run the plane into stuff.
OK, ill probably need a new gearbox then soon...the plane is remarkably well put together and durable for 90 bucks.
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Old Oct 19, 2010, 12:17 AM
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East Bethel, MN USA
Joined Jul 2009
11,750 Posts
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Originally Posted by SkyCadet View Post
Hello!

Well, as much as I was sure that this would work, that little motor just cannot turn the blades fast enough to get enough consistent thrust to keep her flying. Even trimming the blades with a dremmel to 4.4", this was barely enough to keep the plane flying other than at near WOT [at least 75% throttle was needed to keep her aloft].

So, Champ#2 will be eventually retro-fitted with a brushless 1S outrunner, and the stock motor will serve as a spare for Champ #1. I'll use the smaller 3-blade with the BL motor for trials, as many small BL motors are lighter than the stock motor, which will aid in balance.

That'll be a bit yet, probably a late fall project... Have some other priorities with my larger models to complete...

Skycadet
Skycadet,

Problem is - given the same blade design - the more blades, the less efficient the prop. Full-scale planes don't use 3 or 4-bladed props because they're more efficient. They use them primarily in cases where a two-blade prop of sufficient diameter to absorb the engine's power would be long enough to present a ground-clearance problem, mechanical design problem, or when the tips would go supersonic. They also use them because they're typically quieter than a two-blade design that can absorb the same amount of power.

A one-blade prop is the most efficient. Some control-line racers used (use?) one-bladed props that have a streamlined counter-weight where the other blade should be.

Joel
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Old Oct 19, 2010, 08:09 AM
DX5e fatal flaw- PM me!!!!
United States, NY, Cortland
Joined Sep 2010
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Quote:
Originally Posted by iceman88 View Post
OK, ill probably need a new gearbox then soon...the plane is remarkably well put together and durable for 90 bucks.
The gearbox is quite tough, the propshaft bends or the gearbox comes loose before anything really happens to the gears or the plastic itself.

Dave
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Old Oct 19, 2010, 11:56 AM
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Canada, MB, Winnipeg
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Originally Posted by turboparker View Post
Skycadet,

Problem is - given the same blade design - the more blades, the less efficient the prop. Full-scale planes don't use 3 or 4-bladed props because they're more efficient. They use them primarily in cases where a two-blade prop of sufficient diameter to absorb the engine's power would be long enough to present a ground-clearance problem, mechanical design problem, or when the tips would go supersonic. They also use them because they're typically quieter than a two-blade design that can absorb the same amount of power.

A one-blade prop is the most efficient. Some control-line racers used (use?) one-bladed props that have a streamlined counter-weight where the other blade should be.

Joel
This is true for the most part, but not always. As an example, my Super decathlon BL and Lancair ES both have MAS 3-blades on them. The pull is much more than 2-blades of the same diameter, by about 30% or so, while the current draw is only 8-10% [measured in line], yet the RPM at WOT is 90% or so of the 2-blade versions. Static and sim tests using Motor and Drive Calc confirm this, as do real world flight tests.

My problem with the Micro is that I don't have an easy way to test this without getting a whole whap of connectors and converters to the small micro connector, and this will most likely skew results due to the introduction a lot of extra loss that is less of an issue with the bigger planes. Also, the torque on the little Champ motor system seems very sensitive to loads, comparatively.

While the little 3-blader works, I think my issue is that the stock power system just does not turn the blades fast enough for a thrust advantage. I figured it might be a coin toss anyway. I'll convert that Champ #2 to brushless with a AP05 motor, and then try again.

SC
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Old Oct 19, 2010, 12:15 PM
Segelfliegen bedeutet Freiheit
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Canada, MB, Winnipeg
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Quote:
Originally Posted by turboparker View Post
Skycadet,

Problem is - given the same blade design - the more blades, the less efficient the prop. Full-scale planes don't use 3 or 4-bladed props because they're more efficient. They use them primarily in cases where a two-blade prop of sufficient diameter to absorb the engine's power would be long enough to present a ground-clearance problem, mechanical design problem, or when the tips would go supersonic. They also use them because they're typically quieter than a two-blade design that can absorb the same amount of power.

A one-blade prop is the most efficient. Some control-line racers used (use?) one-bladed props that have a streamlined counter-weight where the other blade should be.

Joel
Joel:

Your information is not entriely right - there is a current trend in full scale aviation to go to 3-blades. I have seen this many times, as the 3-blades offer some advantages: ground clearance, smoother running, and depending upon the prop choice, in some cases much quieter running too.

>2 bladed props also do not suffer from OOP [out of plane] inertial moments generated by gyroscopic forces acting on the blades each rotation. This is why they are generally quieter and smoother running.

while 3-blades add an extra blade to add to tip drag, some additional drag due to extra blade area, and so on, in general, with the flight characteristics of these small park flyers, we're far from trans sonic on tip speeds anyway. The 3 blades can be made or chosen to be very efficient, however, we're somewhat limited in choices on smaller models.

Darren/Skycadet
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Old Oct 19, 2010, 06:02 PM
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Rock Hill, SC
Joined Oct 2002
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Originally Posted by FLAME747 View Post
Just ordered some 240 mah Hyperions from RCBABBLE and some GWS 5045 props, and prop inserts from Radical RC FCA
Before switching props, and that in itself will be a neat study, just fly the plane as aggressively as you wish, with the stock prop and the Hyperion 240 mAh battery. You will be surprised just how nice the plane flys "stock", other than the battery change. I consistently get 14-16 minute flights with the 240cell, and there are lots of loops (inside), wing overs, barrel rolls, and WOT flyby's included in the performance. I haven't tried the prop swap yet. Haven't gotten bored enough with the stock setup!


RD
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Old Oct 19, 2010, 08:22 PM
Static Model Collector LOL
Katy, TX
Joined Dec 2009
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Quote:
Originally Posted by Doug Sipprell View Post
Before switching props, and that in itself will be a neat study, just fly the plane as aggressively as you wish, with the stock prop and the Hyperion 240 mAh battery. You will be surprised just how nice the plane flys "stock", other than the battery change. I consistently get 14-16 minute flights with the 240cell, and there are lots of loops (inside), wing overs, barrel rolls, and WOT flyby's included in the performance. I haven't tried the prop swap yet. Haven't gotten bored enough with the stock setup!


RD
Hi RD,

I was thinking about doing that, so I could provide some feedback on how both prop's felt, not anything technical, but just an overall feel.

Anyhow when did you place your pack, can you post a pic - I'm a visual type of guy

BTW: I have been recommending this plane to everyone under the sun, just love it

Thanks,

FCA
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Old Oct 19, 2010, 10:37 PM
Elfi Flyer
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Rock Hill, SC
Joined Oct 2002
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Originally Posted by FLAME747 View Post
Anyhow when did you place your pack, can you post a pic - I'm a visual type of guy FCA
I think you mean "where" did I place or locate the battery pack. If so, this is where.........


RD
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Old Oct 19, 2010, 11:57 PM
Gopher huntin' stick jockey
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East Bethel, MN USA
Joined Jul 2009
11,750 Posts
Quote:
Originally Posted by SkyCadet View Post
This is true for the most part, but not always. As an example, my Super decathlon BL and Lancair ES both have MAS 3-blades on them. The pull is much more than 2-blades of the same diameter, by about 30% or so, while the current draw is only 8-10% [measured in line], yet the RPM at WOT is 90% or so of the 2-blade versions. Static and sim tests using Motor and Drive Calc confirm this, as do real world flight tests.

My problem with the Micro is that I don't have an easy way to test this without getting a whole whap of connectors and converters to the small micro connector, and this will most likely skew results due to the introduction a lot of extra loss that is less of an issue with the bigger planes. Also, the torque on the little Champ motor system seems very sensitive to loads, comparatively.

While the little 3-blader works, I think my issue is that the stock power system just does not turn the blades fast enough for a thrust advantage. I figured it might be a coin toss anyway. I'll convert that Champ #2 to brushless with a AP05 motor, and then try again.

SC
SC,

I was specifically referring to props that load the motor the same - props that have the same static RPM @ WOT - not 2 & 3-blade props of the same diameter.

Joel
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Old Oct 20, 2010, 12:07 AM
Gopher huntin' stick jockey
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East Bethel, MN USA
Joined Jul 2009
11,750 Posts
Quote:
Originally Posted by SkyCadet View Post
Joel:

Your information is not entriely right - there is a current trend in full scale aviation to go to 3-blades. I have seen this many times, as the 3-blades offer some advantages: ground clearance, smoother running, and depending upon the prop choice, in some cases much quieter running too.

>2 bladed props also do not suffer from OOP [out of plane] inertial moments generated by gyroscopic forces acting on the blades each rotation. This is why they are generally quieter and smoother running.

while 3-blades add an extra blade to add to tip drag, some additional drag due to extra blade area, and so on, in general, with the flight characteristics of these small park flyers, we're far from trans sonic on tip speeds anyway. The 3 blades can be made or chosen to be very efficient, however, we're somewhat limited in choices on smaller models.

Darren/Skycadet
Darren,

Regarding full-scale aviation - I stated the same thing in my post. I said that the reason they use 3 or more blades is not because they're more efficient - it's because of ground-clearance, transonic problems, & noise.

In my experience with RC planes, I have yet to find a 3 or 4-blade prop that can outperform a well-designed 2-blade prop that's well-matched to the powerplant & airframe.

Joel
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Old Oct 20, 2010, 09:03 AM
I LIKE WAFFLES....
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Powder Springs, GA
Joined Sep 2010
2,452 Posts
So --- parts have been rolling in --- I think I am just about all set to start my build thread... but can some1 post pics/ideas/suggestions of wing reinforcement? My Champ will pick up more power, but also more weight... I just wanna be sure that the wings are up for allI can toss at it.
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Last edited by SENTRY 62; Oct 20, 2010 at 09:52 AM.
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