NAN Compass GPS

[BobM]

Not sure if this should be here or in the GPS Triangle Course section..



I recently purchased a NAN Compass GPS and it is really amazing. I thought I would share a bit about it and some build information.

The specs are as follows:

4.780m span, 102.5 dm2 wing area, ready to fly weight without ballast for mine is 4.465 kg

I purchased the airframe from SoaringUSA, They did a great job of packing and boxing it so it was safely shipped without any damage.



After opening it up and removing the packing material I was able to look at the components: wing tips, inner wing panels, horizontal stab/elevator, vertical stab/rudder, front fuselage, rear tailboom, and an accessory bag with the wing joiners and servo cover sheets.



All parts are extremely well made and the fit is excellent for all components.

[BobM]

The recommended power system for the Compass is a 3s/4s setup using a Neu 1509 1.5D with a 6.7:1 gear drive. ESC would be a Castle Creations Phoenix Edge Lite HV 160. Prop would be a GM 17-13 and GM spinner. Batteries would likely be 3s or 4s 3700mAh to 5000mAh with a minimum of 45c to 50c discharge. Based on calculations I made on eCalc, this would have an amp draw of 125A or even greater.

I did some research and found that similar 5m GPS sport planes are typically using 6s setups with a 90 to 125 amp ESC. There are several options I considered and ran numbers on eCalc to check...these are the options I found...there are many more options of course...

Hacker C50-9L Competition with a 6.7:1 gear drive, YGE 95LVT ESC, and using a GM 18-10 prop. 6s batteries 2200mAh to 3200mAh 45c to 50c

Leomotion 4023 2400 with a 6.7:1 gear drive, YGE 95LVT ESC, and using a GM 18-10 prop. 6s batteries 2200mAh to 3200mAh 45c to 50c

Schambeck Powerline 1930/9, YGE 95LVT ESC, and using a GM 18-10 prop. 6s batteries 2200mAh to 3200mAh 45c to 50c

Neu 1512 2D with a 6.7:1 great drive, YGE 95LVT ESC, and using a GM 18-10 prop. 6s batteries 2200mAh to 3200mAh 45c to 50c



I picked the Leomotion 4023 2400 with a 6.7:1 gear drive. I selected the YGE 95LVT for the esc and am currently using Spectrum 6s 3200 Mac 50c packs



MKS servos throughout the airframe.

For the rudder and elevator I use MKS 6150 wing mount servos.



For the wings I am using MKS 6130 servos for the flaps and inner ailerons.



And for the tip ailerons I am using MKS 6120 servos. (shown in the Tomas Liu Studio LDS servo mounts)



The wings use LDS mounts and control drives throughout, these are from Tomas Liu Studio. The parts are well made, using carbon fiber laminates and machined aluminum.



For all LDS servo mounts, the PNC machined aluminum motor mount, and any other parts glued into the wings or fuselage I used Locktite 9460 Hysol as the adhesive. This is a 2 part adhesive that is extremely strong. I also used glue syringes wit large gauge glue tips for applying the Hysol. This helped with the application of the Hysol by making it easy to control the volume applied as well as reach places that would be challenging otherwise.



Finally, the GPS system I am using is from RC Electronics. I contacted Rick Shelby, as he is the US representative for RC Electronics. Rick was extremely helpful with my questions and took time to explain all the components that are possible to use. I decided to go with the new Raven 2 Pro in the fuselage. This transmits to the ground unit, which is a Snipe, attached to a cell phone with the Albatross app. All works very well. I also put a very small BlueTooth transmitter on the audio out of the Snipe and use Shokz headphones for hearing the audio output when flying.

[BobM]

Once I had everything organized I started with the servo installation on the inner wing panels and tip panels.

The first steps were to build the LDS mounts and the control horns. This was an easy process using the servo kits that I had form Tomas Liu Studio.

I wrote a quick email to Tomas before starting the build. He was able to recommend the control horn sizes and also the servo arm sizes that would likely work very well for the Compass. He also had hardware for the rudder and elevator.

The servos are mounted into the side frames and then the servo horn support is glued into place 90 degrees from the side frames. Some light sanding and cleanup and then CA is used for joining the pieces together.

The control horns are also carbon laminate. These are made into pairs with a cross piece for each control surface. The 2 large control horns on the left are for the flaps and the smaller 4 horns on the right are for the inner and tip ailerons.



I let everything set for a day to make sure the CA had fully cured. Then I started with working on mounting the control horns into the wing surfaces.

I trial fit all mounts into the spaces and made careful measurements of the linkage length that was required. Once I knew these lengths I was able to cut down the linkages to the correct lengths.



With the horns ready to go I had to open up the spaces where the control horns would eventually be glued. Taking a deep breath, after countless measurements and confirmations, I cut into the wings for the control horns.



I found that it was helpful to attache a thin layer of balsa to the top of the control horn and then gradually sand this down to the correct height and angle to the horn nestles into the trailing edge surface snuggly in the correct position to the hinge line. I made careful measurements for all surfaces and the hinge line measurements, then sanded to the correct placement position. The one below is before sanding and shaping.



After getting the proper fit for all 6 control horns I attached a link so I could glue these in place and make sure they are in the correct positions as well as 90 degrees to the hinge line.

Once in place and the Hysol had fully cured (2 days later), I was ready to install the servo mounts.

The servo mounts were all installed as a dry run, without any Hysol. I did this a couple times to make sure of the sequence for installing the mounts correctly once the Hysol was applied. Fortunately the Hysol has a working time of about 45 to 55 minutes, which allows adjustments to be made before everything starts to set.

To install the mounts in the correct position I had to make sure the servo arms were centered correctly as well as make sure of the linkage lengths. Once this was all set I was ready to use the Hysol and install.

I attached all linkages once the servos and mounts were in place with the Hysol applied. The trail edge surface s were carefully taped in their neutral positions, which then made it possible for the servos to be glued in the correct position. I complete 2 servo installations at a time....first the flaps, then waited a day or so, then the inner ailerons, waited a day or so, and finally the tip ailerons.

The end result was excellent, with only very minor trim changes once everything was mounted and the Hysol had full cured. The picture below is of one of the flap servos installed. There is a small amount of Hysol squeeze. out that can be seen in the bottom left of the mount.

[BobM]

The fuselage for the Compass is two pieces: the front section of the fuselage and the rear tailboom. This makes transport relatively easy as the sections break down to very manageable lengths that easily fit into the car.

A carbon fiber tub tray is provided for the elevator and rudder servos to be mounted.

There are many different possibilities of how to mount these, as well as a wide range of servo choices,

My first thought was to use the MKS 6150 with standard mounting surfaces, which are typical of servos mounted into a fuselage. A tried some ideas out for these servos and made some prototype mounting blocks. In the end I found the mounting system seemed to be too easy to get out of alignment when being glued up...too many pieces to make the blocks work.

I then got the wing mount versions of the MKS 6150 servos and used a 6mm thick block of carbon fiber laminate to create the mount that would fit into the tub tray.

Staring with the dimensions of the tray I made a rectangular block the servos would eventually be attached to.



I used the servos to determine placement in the block and then carefully machined the block with various tools so the servos could be screwed into place. The fit of everything was checked multiple times and then the 6mm tray was glued into place in the tub tray using Hysol.



Once the Hysol had full cured I put the servos in place to test the fit...all went very well.



I made a servo connection point on the tailback to make it easy to remove. I used a male and female MPX connector and made short servo leads. The wires are soldered to the MPX connector and they have JR female ends for connecting to the servos.

I mounted the MPX connector to the tailboom using brass standoffs that I found on Amazon. These are 2.5mm threaded standoffs with camfer head machine screws to hold things in place.



The standoffs are screwed and attached to the MPX connector, then I carefully used mold release on the connector and glued into place in the tailboom with Hysol. This was a two step process with the initial glue to hold things well enough. Once the Hysol set from the first round I took out the connector and applied a bit more Hysol on the brass standoffs to make sure everything stayed in place.



The finished boom with the MPX connector.



Here is the finished tailboom after the tub tray is glued into place. Again, I used Hysol for this.

[BobM]

The front portion of the fuselage was next. It has to hold several components including the ESC, the receiver, the battery, and the GPS unit (a Raven 2 Pro).

I mounted the motor and had the placement of the ESC set. Using this I started to place the other components. I got the idea of a removable try for Aaro's Compass thread on RC Groups.

He has a very clever design with the tray and made it removable. This allows easy access to all components if need.



The tray is 2mm FiberGlass that I found on Amazon. Easy to order and arrived the next day. I made a balsa tray to start with, which allowed me to continually modify it as needed to fit. into the space of the fuselage opening.

There are 2 attachment points in the front, where I use 2.5mm machine screws for holding the try in position. Again, I used the brass standoffs as attachment points for the screws with Hysol to glue them into place. They are to the left and right of the ESC at the top of the picture. A 2mm Allen wrench is all that is needed to remove the tray.



I mounted the Raven 2 Pro on the tray with double sided 3M tape. It is a gel type tape with very strong adhesive ability. The GPS receiver it mounted onto of the Raven 2 Pro with heavy duty plastic 3M velcro, the clear plastic kind that really holds things in place. This makes it easy to remove the GPS receiver and pull the tray if needed.



The back of the tray slips into tabs that are glued onto the fuselage with Hysol. They are just to the left and right of the receiver and slightly above. I gave about 1/8" to 1/4" clearance for the tray above the receiver and ESC .



Here is the tray in place in the back tabs.



Below the tray are the receiver and ESC



On the nose is the GM spinner and propellor. The spinner size is 36mm and the prop I am currently using is a GM 18-10 folding thin blade prop.



My only concern with this spinner is the lack of airflow, no matter how little it may be.

I also have a RFM 36mm spinner that has a ventilation hole in the tip of the nose. I am thinking I will change out the spinner to get as much airflow into the fuselage and access the components as possible.

[BobM]

I had a chance to get several flights with the Compass when I was at Cumberland last week.

I used Spektrum 6s 3200 mAh 50c packs for these flights. Ready to fly it weighs in at 4.465 kg without ballast. There are ballast tubes in the main wing panels, so it can be ballasted to the limit of 7kg if desired.

With the pack used I found the CG of the Compass to be at 115mm from the leading edge. During flights I did a dive test and found this to be a bit nose heavy. I also found that I only used approximately 20% of the pack for any given flight, with multiple climbs to altitudes of 200m to 300m.

I have some 6s 2200 mAh 45c packs on the way. I am hopeful to lower weight of these will help move the CG closer to 125mm, which is what others have suggested for the Compass without ballast.

The Compass flies incredibly well, even with me at the controls ! It thermals with the lightest lift and will fly well at a range of speeds.

Landing is pretty easy with the flaps. They are of good size and slow the plane down effectively with an elevator mix.

I am just getting it set up and have 3 flight modes I am sorting out: Cruise, Thermal, and Speed.

Being new to GPS I only flew a dozen or so laps total out of all the flights I had (learning how the GPS worked and getting used to the triangle course I was able to get about 1 to 4 laps on any individual flight).

Now all I have to do is keep the Compass straight on course, maintain altitude and speed and I'll be all set....easier said than done !!

It is really an excellent sailplane.

[mlachow]

Did you set up the telemetry from the YGE controller. It's nice to have the actual battery pack voltage. I can't believe they recommended a 3s or 4s setup. I use a dual battery zepsus switch on my Paradigm so I can have a backup 18500 2-cell pack just in case.

You need access to the GPS device periodically to clean out old flight logs. I think with the Raven Pro 2, you just need to make a USB connection. With a Swift you needed to get to the memory card to clear out the old flights.

[BobM]

I haven't set up the telemetry for the YGE yet...one of my next steps with the Compass. The telemetry should work with the PowerBox/Core system I'm now using.

Thanks for the note about accessing the Raven...with the fuselage tray set up I made it is very easy access and connect a usb cable to the laptop or other devices for updating and maintaining everything.

[Curtis Suter]

Bob,

Have you hand launched this with max ballast i.e. ~7kg? How does it do? Enough power to not worry about it?
All the best and Hope you have many Triangles, well just one less than me if we ever fly together! Ha ha
Curtis

[BobM]

Hi Curtis, sorry about the delay replying here. I don't have mine ballasted to full weight of 7kg currently. I'm still flying at the unballasted weight of 4.465kg. With the wingspan and weight it can be a bit awkward for launch, especially if there is wind or turbulence...but...it is manageable as long as I hold the fuselage firmly...seems like there is more than enough area to hold the fuselage enough for all the launches I've had so far (between the leading edge of the wing and just behind the canopy). I have read reports form others flying the Compass with full ballast at 7kg and they have been able to launch by hand.