HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Mar 22, 2010, 05:53 AM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
Quote:
Originally Posted by #cherokee View Post
I was testing the electrics on my 2500 Watts Up today.

I am using a 300 watt BRC inrunner driving a 4.4:1 maxon copy gearbox, 11.1 volts, 2700kV, I had fitted the largest prop I had available a 13 x 5 aeronaut , target weight of complete model is 1200g.

Wattmeter showed 169 watts and 16 amps.

Which prop should I change to a 14 x 9/10 or maybe a 15 x 10 ?
It depends on what you want to use it for. For 200 Watt comps, you would need to be at 240 watts for the target weight of 1200 grams/1.2 kilo.
If using an Height Limiter it does not matter, or for sport flying, providing you do not exceed the motors 300 watts or the ESC capacity.
As a guess I would try 14X9, as that used to give me near the figure of 240 watts on my early Alacrity's.
Going up in dia gives a big jumps in current draw/watts, pitch change does not give such a big increase.
Have you used the calculator link that I put in an earlier post? http://brantuas.com/ezcalc/dma1.asp

Nice to hear that you are near flying it.

PS Had a play on the link above & a 13X8 or 14X6 come close to what you were aiming for.
Essex BOF is offline Find More Posts by Essex BOF
Last edited by Essex BOF; Mar 22, 2010 at 06:09 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 22, 2010, 09:51 AM
Registered User
Sussex, UK
Joined Dec 2009
8 Posts
Props

Thank you Brian, I will try a 14x9 for starters, I have a 40A ESC.

The fuselage is finished and painted, tail feathers all done with just the rudder and elevator links to finalise, ( I am using 2mm rod ).

I need to do the final shaping and sanding on the wings and then cover and install the spoiler servo (SD150). I hope to test fly at Easter, unfortunately my wife is dragging me off to the Canary Islands tomorrow for a week.
Incidentally I assume you glue the inner and outer wings together before covering, I am using transparent Profilm.
#cherokee is offline Find More Posts by #cherokee
Reply With Quote
Old Mar 22, 2010, 12:14 PM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
Yes you cover the wing tip panels, with outer tips glued on. I cover inner panel first, then attach outer panel covering to the top of inner covering..
Hopefully if you do have an accident & knock the tip off, it does not take any iner covering with it.
Essex BOF is offline Find More Posts by Essex BOF
Reply With Quote
Old Mar 26, 2010, 07:19 AM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
There is a competition on 4th April at Bartletts Farm Essex for electric gliders, so where are all these Watts Up that are being built, in the Essex,Kent,Suffolk areas, that could enter it.?
Come on give it a try, what other comps gives you 7 flights in a day!!!!!!
Essex BOF is offline Find More Posts by Essex BOF
Last edited by Essex BOF; Mar 26, 2010 at 01:15 PM.
Reply With Quote
Old Mar 26, 2010, 08:02 AM
Gnd/Heli Interface Tester
jiberjaber's Avatar
Essex UK
Joined Jul 2005
359 Posts
Unfortunatly I won't be able to make this as I havent got anything to fly at the moment... however, if you have something, get yourself along...



You may even see the Bof himself!

jiberjaber is online now Find More Posts by jiberjaber
Reply With Quote
Old Mar 26, 2010, 08:14 AM
Don't ask me anything...
Woodstock 1's Avatar
Ireland, County Kerry, Kerry
Joined Dec 2005
6,885 Posts
Quote:
Originally Posted by Essex BOF View Post
I would advise build the standard version then build the larger tips at a later date.
I've been mulling this over since you posted that, and I cannot work out why you say that? I have zero interest in a 2.5 m glider.
Woodstock 1 is offline Find More Posts by Woodstock 1
Reply With Quote
Old Mar 26, 2010, 01:12 PM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
Quote:
Originally Posted by cvanscho View Post
I've been mulling this over since you posted that, and I cannot work out why you say that? I have zero interest in a 2.5 m glider.
It all depends on what you are going to use it for. All round flying in wind speeds of up to 15mph, the 2.5M will be more controlable & penetrate better with the higher wing loading.
For floating about in light winds or balmy summer evenings, the 3.1M would be hard to beat.

So you have a choice, how bad is that
Essex BOF is offline Find More Posts by Essex BOF
Reply With Quote
Old Apr 01, 2010, 02:24 AM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
Quote:
Originally Posted by Essex BOF View Post
There is a competition on 4th April at Bartletts Farm Essex for electric gliders, so where are all these Watts Up that are being built, in the Essex,Kent,Suffolk areas, that could enter it.?
Come on give it a try, what other comps gives you 7 flights in a day!!!!!!
Have had to cancel the above comp due to the terrible weather that we are now having & is forecast for the weekend. No doubt the Sunday will be perfect now, but the site is also not in a fit state to take traffic at the present time.
Calendar looks congested, so will not be able to re schedule till a later date.

So first comp now would be May 2nd, for the Leaque
Essex BOF is offline Find More Posts by Essex BOF
Last edited by Essex BOF; Apr 04, 2010 at 05:48 AM.
Reply With Quote
Old Apr 13, 2010, 09:24 AM
Registered User
Joined Jan 2008
7 Posts
Motor and ESC Choice

Hi all, Hope you can help me. The plane is almost complete but I need to get a power train sorted out. I am new to this having only flown ARTF models before (complete with motors and esc etc). I looked at the Hacker A20 with a gearbox but was then told I needed an esc for 85 as well. This seems very pricey as a solution.

Someone else mentioned Hyperion Z-3025/10 or12 as a solution. The problem is I could do with a shopping list of which motor, esc, prop.

All help greatly appreciated - sorry to ask.
keefy is offline Find More Posts by keefy
Reply With Quote
Old Apr 13, 2010, 02:35 PM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
Quote:
Originally Posted by keefy View Post
Hi all, Hope you can help me. The plane is almost complete but I need to get a power train sorted out. I am new to this having only flown ARTF models before (complete with motors and esc etc). I looked at the Hacker A20 with a gearbox but was then told I needed an esc for 85 as well. This seems very pricey as a solution.

Someone else mentioned Hyperion Z-3025/10 or12 as a solution. The problem is I could do with a shopping list of which motor, esc, prop.

All help greatly appreciated - sorry to ask.


You will need an ESC regardless of what motor & setup.
For Hyperion Motors, go to Robotbirds (http://robotbirds.com/catalog/index....86f05453871bed) they will point you in the right direction as to what you need with the motor if you buy it from them. Give them a ring, they are quite helpful.
Seaching round other supplier's will probably result in a cheaper package & going through this thread will give a good guide.

A good ESC should be about 25/30 for a 40 amp one
Essex BOF is offline Find More Posts by Essex BOF
Reply With Quote
Old Apr 14, 2010, 03:06 AM
Registered User
Joined Jan 2008
7 Posts
power train continued

Quote:
Originally Posted by Essex BOF View Post
You will need an ESC regardless of what motor & setup.
For Hyperion Motors, go to Robotbirds (http://robotbirds.com/catalog/index....86f05453871bed) they will point you in the right direction as to what you need with the motor if you buy it from them. Give them a ring, they are quite helpful.
Seaching round other supplier's will probably result in a cheaper package & going through this thread will give a good guide.

A good ESC should be about 25/30 for a 40 amp one
What size prop should I be using? with the hyperion motor and esc, any ideas please
keefy is offline Find More Posts by keefy
Reply With Quote
Old Apr 14, 2010, 04:56 AM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
Quote:
Originally Posted by keefy View Post
What size prop should I be using? with the hyperion motor and esc, any ideas please
http://robotbirds.com/catalog/images/hyperion/3025.pdf
They do not show folding prop figure on there chart, for the 3025/12 but give the following for an APC 13X6.5 on 3Cells of 26Amps,6400rpm at 265Watts.
So a folder approx that size should not be that different, probably you could increase the pitch to 13X9 or 10 in a folder.
If you only sport fly then the 13X6.5 folder will do, as you will be well within the capacity of a 40amp ESC
Essex BOF is offline Find More Posts by Essex BOF
Reply With Quote
Old Apr 20, 2010, 07:15 AM
Registered User
Sussex, UK
Joined Dec 2009
8 Posts
Maiden Flight Watts Up 2500

Model was test flown on Sunday at the Ashurst field by Chris Foss and was great. It went up like a rocket, needed no trim, it just needs some down elevator programmed in on the climb, and a little more elevator when full spoiler is deployed.
I bit the bullet and fitted a Hacker A20 with a genuine maxon gearbox and a 14x9 prop because I was not happy with cheaper alternatives.
All up weight came in at 1150 grammes.
On the group photo taken at Ashurst and posted by Bernie and Martin Bell in the Ashurst results site the model is on the extreme left (and me).

Thanks go to Brian for the design and help during the build.

All I need to do now is get some practise in before the next comp in May.
#cherokee is offline Find More Posts by #cherokee
Reply With Quote
Old Apr 20, 2010, 12:21 PM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
Quote:
Originally Posted by #cherokee View Post
Model was test flown on Sunday at the Ashurst field by Chris Foss and was great. It went up like a rocket, needed no trim, it just needs some down elevator programmed in on the climb, and a little more elevator when full spoiler is deployed.
I bit the bullet and fitted a Hacker A20 with a genuine maxon gearbox and a 14x9 prop because I was not happy with cheaper alternatives.
All up weight came in at 1150 grammes.
On the group photo taken at Ashurst and posted by Bernie and Martin Bell in the Ashurst results site the model is on the extreme left (and me).

Thanks go to Brian for the design and help during the build.

All I need to do now is get some practise in before the next comp in May.
Looks good & nice to see one built & flown on the thread. Pity you did not trim it out & fly it in the comp as it was an ideal day to fly.
I think your light weight is down to the Hacker A20 which is a lighter power unit than the one I used.

One advantage of this design over others is the ability to be able to ballast it up in more windy conditions, with so much room under the CG position in the fuselage. You can always add weight, but you cannot take it out
Essex BOF is offline Find More Posts by Essex BOF
Reply With Quote
Old Apr 26, 2010, 11:27 AM
Registered User
Essex BOF's Avatar
Joined Sep 2009
361 Posts
I was at a comp yesterday, where a guy was flying a Watts Up.

When the motor cut the model went into what looked like a death dive, which then developed into a bunt which he managed to recover from then lost orientation, landed hard breaking the wing in the process.

I was interested in what had caused this & it transpired that he had arranged the motor control on what was in fact the spoiler switch & vice versa for the spoiler. so he had activated the spoiler instead of cutting the motor.

A bit of advice here, never change what you normally use for your setup on the controls, as it is all to easy in the heat of the moment to get it wrong
Essex BOF is offline Find More Posts by Essex BOF
Reply With Quote
Reply


Thread Tools