View Full Version : Considering Upgrade of GP Spectra

08-01-2005, 08:23 PM
I am considering upgrading my stock Spectra or buying a park flyer.

Considering the Spectra, what would be your suggestions for upgrading the motor/battery/gear drive for better performance and longer run times ?

I have the following receiver with built in esc. I would like the suggestions to consider items the reciever/esc can handle.

Thanks !

Jason T
08-02-2005, 01:13 AM
Which motor and battery are stock with the GP Spectra?

Unfortunately, I am not familar with the esc you mentioned. But looking at the specs it looks like it says continous maximum current of 100A is that correct or is that 10A?

08-02-2005, 01:52 PM
According to the specs for a new one, the motor is a T601. I have used 7 cell 1500mah batteries the last time i flew.

The 100A info is straight from the owners manual for the radio/receiver.

08-02-2005, 01:59 PM
Heres some more info from the manual:

The MCR-4A can control 280 class to 540 class motors.
•6V (5 batteries), 7.2 V (6 batteries), or 8.4 V (7 batteries) NiCd
battery pack can be used with the MCR-4A. (When using a 540
class, etc. motor, purchase an NiCd battery pack connector off the
market. Be sure that the (+) and (—) polarities are correct. If the
(+) and (—) connections are reversed, the MCR-4A may be damaged
beyond repair.)

Jason T
08-03-2005, 12:32 AM
The first question to ask when wanting to upgrade is how much do you want to spend? :) That will help narrow down the choices.

08-03-2005, 02:47 AM
I've considered the Spectra in the past, but it seems HEAVY to me. What weight ranges are you guys seeing?

Jason T
08-04-2005, 11:53 AM
Depending on the setup I have heard the AUW being in the 38 - 44 oz range.

08-05-2005, 02:24 PM
Currently running an 8 cell 1700 nimh pack, they may be 1800's or something now. Jeti 16/15/4 brushless motor direct drive, 8-4 Sonictronics folding prop, Jeti 30 esc although I would use a CC 25 or 35 now for the possiblility of using lipos. I get 3 or 4 very high climbs on my setup and steep climbs. No comparison to stock. I have tried a Thunder Power 2100 3s lipo pack but it gets hotter than I like, but sends the Spectra straight up.
Not sure about the ARF, but I built the kit in 1991 and it came out about 50 oz. RTF. Of course that was with heavy 7 cell sub C's. I first flew it with no esc and a 2 channel radio.
For the very best performance I understand that a geared brushless motor swinging a larger prop would be best, but don't have experience with that.

08-08-2005, 12:03 AM
I'm running the planetary Astroflight 020 setup on a 3 cell Kokam 2000 with a 14X8 carbon-fiber Aero-naut folder. Nearly vertical performance at less than 30 amps! Lighter than stock by about half a pound! Under some recent (most favorable) conditions, I could have had it 'spec'ed' most of the day, but had to go back to work from lunch hour.

08-11-2005, 07:19 PM
I went ahead and got a parkzone Piper J3. It was local, it was relatively inexpensive, and i am not a doctor (read, no patience)....

I appreciate the responses though, as I will be looking to upgrade the spectra into a more pleasurable experience.

Thanks again,

10-04-2005, 05:15 AM
Low cost solution:

Add a 2.5 to 3.1 gear box to the stock motor and a 11X 7 or 11X 8 folding
prop. On the stock 7 cells the climb will be in the 30 degree neighborhood
and will be much stronger with good climb in moderate winds. This is no
hotliner, but it will take it up to height much better and much faster and you
will likely get an extra climb in the bargain. Go to 8 cells and the climb
can actually feel pretty strong. :)


About 15-$20 for the gearbox and about $15-$20 for new blades for the folding
prop. You may need to remount the motor to accommodate the gearbox and you
will have to reverse the wires to change the rotation of the motor. There are
more expensive gearboxes that will fit better and don't require reversing the
motor. Or you can buy a packaged motor/gearbox that is all set to go.

I have given you the low cost solution. If you are building the ARF or kit,
these are easy additions that will make your new e-glider fly much better for
a modest additional investment.

Here are examples:
http://www.electrifly.com/motors/speed600.html (http://www.electrifly.com/motors/speed600.html)
Geared systems - tower
http://www2.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=600gd&FVPROFIL (http://www2.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=600gd&FVPROFIL)=++

As a higher cost, higher performance alternative, you can go to a brushless
motor/gearbox combo. Here is one example that looks like a good choice on
8-10 cells or 3 cell lithium that can handle 35 amps. On this set-up these
planes should have strong, 45 degree or better climb angles and probably an
extra climb or two.

MJ20152 MPJet AC 26/45-20 D Brushless Motor with 2.8:1 Gearbox ..... $ 68.90
An 11X8 prop should do fine with this combo.
http://www.hobby-lobby.com/brushless_mpjet.htm (http://www.hobby-lobby.com/brushless_mpjet.htm)
Advance PLUS 30 Amp Brushless Controller $ 90.00
http://www.hobby-lobby.com/jetiblue.htm (http://www.hobby-lobby.com/jetiblue.htm)