Gluonpilot

Update:

I have now made a motor mount out of a simple ply disc which is glued to the back of the fuselage - weight saving approx 20 grams compared to the original.

Also the heavy spar from the kit was replaced bu a c/f 3mm tube which weighs about 5 grams - another weight saving of close to 20 grams!

Total weight as seen in the pictures is now 260 grams which includes motor/ESC and a separate BEC from the Gluonpilot which will not have the extension board.

More to add:

Gluonpilot/GPS/XBee/2xservos/cables: 50 grams
Battery: 90 grams
GoPro: 100 grams

TOTAL: 500 grams

So, it still seems doable to hit 500 gr...
/Björn


/Björn

An old funjet: Nostalgia Where do they still sell it?

I still believe the funjet is one of the best designed flying wings I have owned. It can fly fast and slow with hardly any bad behaviours.

Tom wrote:An old funjet: Nostalgia Where do they still sell it?

I still believe the funjet is one of the best designed flying wings I have owned. It can fly fast and slow with hardly any bad behaviours.

Yes, they still sell it over here so I guess it is still in production...

Here's an update - the Funjet II is now finished and ready for maiden!

- By placing the battery far back, I was able to put the GoPro quite far front and could avoid shortening the nose
- Total weight is now 450 grams including a 3S-1100 Hyperion LiPO and with a 7x5 prop I get about 100W's of power
- With the GoPro mounted (a must to keep the CG right!) the total weight is 550 grams (as some of your predicted
- I decided to skip some weight watching - added an external 2.4 GHz antenna, some fiberglass tape on the underside, added the servo fairings etc.

All in all - it feels lika a good and solid setup and now I am only awating flying weather...

Here are some pictures!

/Bjorn

Wow, that is a nice experimental setup: battery in the back Maybe first a test flight with some weight instead of the GoPro?

I see you also discovered the cheap stick-on antenna from Sparkfun. Good results with it?
I'm also going to move to this type, the digikey stick-on antennas are way too expensive! Be careful: you placed it over the carbon spar. Carbon = conductive = shielding your RF antenna

Björn a very interesting build log!!!

I have some questions : do you use in the same time 2,4 ghz Xbee and 2,4 ghz rc receiver ? There are no interferences?

I am waiting for the mainden flight .

Thank you.

Tom wrote:Wow, that is a nice experimental setup: battery in the back Maybe first a test flight with some weight instead of the GoPro?
I see you also discovered the cheap stick-on antenna from Sparkfun. Good results with it?
I'm also going to move to this type, the digikey stick-on antennas are way too expensive! Be careful: you placed it over the carbon spar. Carbon = conductive = shielding your RF antenna

Thanks and Yes, I had to do that to push the GoPro forward... CG is right but it will still be intersting to see if it plays out well... And opps! Didnt think of that the SFun antenna was right over the spar... If the 3M glue permits I will move it ab bit...

I have some questions : do you use in the same time 2,4 ghz Xbee and 2,4 ghz rc receiver ? There are no interferences?

Yes, I have been using Xbee's on 2.4GHz and Hitec 2.4 systems for quite some time without any issues. Up to 2 km range on the Xbees!

if you make up new wire sets of exactly the correct length, you might want to consider using enameled magnet wire. It is lighter than plastic sheathed wire. If you cut and solder them to exactly the correct length and avoid connectors you can save quite a bit. On the small servos you can use 26 or 28 gauge wire or maybe thinner. It is very hard to solder to the circuit board in the servos. The signal lines from the Rx to the GP can be 32 gauge. Remove all the pins from the GP and direct mount the wire. Take the pins out of the Rx and solder short wires of the exact length to the GP.

The insulation on enameled magnet wire is very tough. It is also very high temperature resistant. You can safely twist the wires together and test for shorts. There is very low chance of them shorting.

These guys use them to save weight and to directly power their motors.

http://grenadeindoor.modelisme.com/747.htm

If you can get some of the correct gauge for the ESC to motor connection you can save weight over the plastic sheathed wires. A good source of this wire is electric motor rewind shops. Many gauges are stocked by most of them, usually in big paper or plastic barrels with 1000s of meters in each

Also directly soldering the ESC to the motor certainly saved weight. The connectors and wires are heavy.

Would the aerodynamics be improved by cutting off the "tip tanks" like the FunJet Ultra? Maybe sand them off and make them an extension of the wing to add wing area. As you have the FunJet Ultra you can compare the wing tip shape to see if the Ultra has extra wing area or just tip tanks cut off.

You can hollow out the canopy with a Roto-Tool sanding drum.

Just some ideas. Weight saving is hard and tedious.

What about removing the GoPro case and mounting it in the canopy.

Jim

Thanks Jim for interesting suggestions. Wiring and connectors is for sure a weight issue.
Your idea made me think we should discuss with Tom to make up one of the next gen GP's with fixed wires for a really small rx and hardwire to GPS/Xbee to make a really small and light complete autopilot...
I am hoping to take up the idea of a really small MAV using the GP for next season.

Cheers,

Björn

You can ask me for a gluonpilot without any connectors!
The GP2 has the switched regulator on the main board, so this should be sufficient for everything. A 15 grams autopilot incl. GPS has become a reality!

I still hope one day to find time to install the gluonpilot in a 25cm plane. Most time will be spent building the model. Maybe a good marketing stunt

The smallest GPS unit is this one: http://shop.trenz-electronic.de/catalog ... ts_id=1096
Only 4 grams Just add a diode & supercap and you're ready to go!

Tom wrote:You can ask me for a gluonpilot without any connectors!
The GP2 has the switched regulator on the main board, so this should be sufficient for everything. A 15 grams autopilot incl. GPS has become a reality!
I still hope one day to find time to install the gluonpilot in a 25cm plane. Most time will be spent building the model. Maybe a good marketing stunt

Consider that an order from me I will add the smallest rx I can find, I think the Hitec 6ch I am using just weighs 2 grams or so without antenna.

I also think I need to do some weight watching on the Xbee board too - I guess hard-wirind to the Xbee itself could be an option but we need 3.3v from the board - is that possible or do we need to add a regulator?

Good to have some ideas during "building season" which starts pretty soon...

/Björn