FG EXCLUSIVE! Wringin' Out The Desert Aircraft DA-85!

[LeadingEdge]

Well lookie what the brown truck dropped off today!

In our never ending quest to bring the latest in modeling products to our members, the good folks at Desert Aircraft have bestowed upon The Giants something very special! The much anticipated DA-85! While the first production runs of this much anticipated gas motor are about to begin, we’re gonna put it through the gauntlet and answer any questions you might have with the help of our friends at DA. Without any further adieu, let’s check this puppy out.

The pre-production test unit that we received is absolutely stunning to look at. This gizzards of this particular unit are exactly to spec of the upcoming production model. Final cosmetic tooling is still in progress which will clean up some of the barely noticeable rough milling areas on the case.

The plane we have chosen to install the motor is a 33% Edge 540 by Hangar9. Weighing in at around 23 pounds, this plane should prove to be a great platform to test the performance of this motor. Throughout the next few days, we’ll take you through our journey from install, to flight with real world, and accurate performance measurements through on board data logging from EagleTree Systems.

Stay tuned to The Giants for comprehensive information and news about this exciting product! We’ll be working on this project throughout the weekend, so check back often for updates to this LeadingEdge article.

And finally, a big thanks for The Desert Aircraft Crew for giving FG the honor to be the first, media outlet to get their hands on the DA-85!

Heeeere we go!

~FlyingGiants Staff

[LeadingEdge]

First off, let's take a closer look at The 85. Again, the unit we received is pre-production and the final results will vary, but nontheless, the eyecandy that we were presented with was simply stunning.

One of the first elements of the motor that immediately stands out is the lightened hub. Pretty sweet! Adding to the asthetics are DA's trademark red hall sensor and associated wiring, carb stand-off and bolts, and of course, the beautifully polished case.

The DA85 is an entirely new motor designed from the ground up, and represents the latest in addition to the wildly successfully lineup of model airplane motors from Desert Aircraft. The muffler in the photos below is a prototyle Slimline Pitts.

Technical specifications:

Displacement: 5.24 ci (85.9 cc)
Output: 8.5 hp
Weight: 4.3 lbs (1.95 kilos)
Bore: 2.047 in (52 mm)
Stroke: 1.59 in (40.49 mm)
Length: 5.9 in (150 mm)

Prop size: 26" - 27x12 2 blade

[LeadingEdge]

The plane we chose to perform flight testing on is a 33% Hangar9 Edge 540 which was previously fitted with an 80cc motor from another manufacturer. Our airframe has only 3 flights. Many people have flown The H9 Edge successfully with 80cc class motors, however it really comes to life when coupled with a 100cc. Somewhere in between resides the perfect power plant, thus our decision to give this airframe a whirl.

Like the DA100 and DA150, The DA85 mounting bracket is designed to be mounted flush, onto a stout surface - use of traditional standoffs are not recommended... Being that this is an entirely new motor, third party mounting devices will soon be developed, and airplane kit designs will adapt to the
mounting requirements of the DA85. In the meantime, as with any motor, we needed to find the best way to mount 'er up.

As people get these motors in their hands, we'll undoubtedly see all kinds of ingenious mounting techniques here on The Giants, but being the "if it ain't broke, don't fix it" kinda guy I am, I opted to tear out and rebuild the firewall on the edge .

My goal was to extend the motor box out approximately 2 1/2 inches from the stock location, bringing the hub flush to the end of the cowl. Looking at the firwall, the measurements turned out to be 7" on the left, and 7 1/4" on the right of the motor box. After alot of measuring, cutting, laminating, and sanding, the new motor box was complete.

[Dean Allison]

Nice!

[LeadingEdge]

While we're waiting for the glue to dry, let's talk about our testing gear. The main items everyone wants to see is RPM's, and head temperature. We're going to keep it simple with our tests, and focus on these numbers. We're going attempt to chart this out, and document mid range response and throttle transition as well as engine temperature throughout each flight.

We will also be wringing the edge out with one of the greatest freestyle and precision pilots in Southern California, Mr. Jeff Szueber! Jeff will also add to this discussion, and provide his feedback as well.

To accomplish all of this, we will be utilizing a killer data logging system from EagleTree Electronics. For those of you not familiar with their products - be sure to check our their website at www.eagletreesystems.com. EagleTree has a full lineup of telemetry products for a wide array of modeling specialties. Various sensors allow the user to log GPS, RPM, servo glitches, voltage, g-force, and stick input data to name a few. Heck, it will even plug your flight path into Google Maps! Data is aggregated, and replayed through EagleTree's Windows based software (Vista works, yay!). I've only scratched the surface on what this system is truly capable of, but what I have seen soo far is truly amazing. The logger is very small and light weight as well. Check it out, it's cool stuff! The resolution of our logging has been pre-programed to 10 samples a second.

For purposes of this test, we will be logging flight data with the EagleTree USB Flight Data Recorder. Head temperature will be acquired through the use to two probes that will fit around the head of the motor, on opposing fins for accuracy. Engine RPM will be logged using an optical RPM sensor. Just for kicks, we will also record glitches, voltage, altitude, and stick movements throughout our flights.

Here's some shots of the EagleTree USB Flight Logger, pre-install.

[Haggy]

Reading with a keen interest...keep up the good work guys!

[LeadingEdge]

Navigation on the edge will be provided by a Spektrum 9 channel module, coupled with a JR 10x, and a AR9000 receiver, with two satellite receivers. Our system will be well powered by 2 2600 Fromeco batteries connected to a two channel Wolverine switch, into a Smart-Fly SuperReg, and finally to a Smart-Fly Power Expander Sport. All deans connections throughout. Similar gear was used for the DA ignition as well.

This is the perfect setup for the demanding power requirements of 2.4ghz gear, and provides clean and consistent voltage under load. Not to mention great redundancy.

Below are some photos of the install of our power and navigation gear. Note the EagleTree USB logger. This EagleTree system came with 4 "Y" harnesses which are typically used to split the signal of each stick input for logging into the computer. One cool aspect of this setup is that we were able to utilize the additional servo ports on the Power Expander for this purpose, thus eliminating the need to split a connection from a channel.

While many use a system like the EagleTree USB logger on a temporary basis, we wanted to mount this puppy in good for future flights.

These photos are a close representation of our final setup.

[LeadingEdge]

After completing, finish sanding, and glassing the motorbox, it was time to install the Desert Aircraft DA-85. We centered the DA-85 on the motorbox (which already had 4 degrees of right thrust built in) using the "ladder" trick. For those of you not familiar with this, we basically duck taped the edge vertically to a ladder and placed the motor on the firewall, installed the cowl, centered everything up, and marked the holes to drill for the mounting ears. Photos intentionally omitted to avoid flaming.

The carb was removed for pre-placement on the firewall, and I had a chance to see the innards of the reed block. This is a very cool, and clean setup, with attention to detail, and of course the obliged Desert Aircraft logo on the side.

Back to mounting. As with all rear carburetor motors, install can be tricky, and patience is golden. Some very strategic cutting of the firewall was required, and we used a bootleg template that we acquired from our spies.. ahem... DownUnder. The final 85 kit will come with all of the necessary, and accurate non-bootleg templates for ease of mounting.

Once the 85 was mounted, it was time to hook up all the linkages, wire up the ignition, regulator, and switches, and plug 'em into the PowerExpander. We decided to go with 2 servos on the 85 - throttle, and choke (snap roll switch, sweet.). The next time we have the motor removed, we'll flip over the choke linkages to the other side for better leverage, but for now, the setup works flawlessly.

This is always the fun part any build project - you see the light at the end of the tunnel, no more coughing balsa dust, and you get to play with all the cool techie gizmos! Here's some shots of the install.

[LeadingEdge]

Moving through the install process, and late into the evening, we sucessfully completed the entire install of all electronics, logging gear, and even programmed our new model into the transmitter.

The first photos below show a closeup of the temperature hoops that wrap around the cylinder head of the DA-85. In the middle of these two hoops is an EagleTree sensor that can measure temperatures up to 400F. Our kit came with two hoops, so we decided to install the both on different fins. The temp sensors then connect to a 3 lead bundle which runs back to our logger.

The last photos are of the EagleTree optical RPM sensor. Now this thing is cool! The sensor contains its own light source, and will accurately read RPM's right off the back of the spinner. Now you're probably wondering why we painted the back of the solid TruTurn spinner black and white. The sensor needs to "see" the color changes in a surface to get the best measurements.

The optical sensor was mounted inside the cowl, and a box was cut out of lightweight balsa to hold it in place. The total distance between the back of the spinner and the sensor is less than 1cm, and was colored black with a Sharpie for sweetness. I can't wait to see how this puppy works! Pretty nifty 'eh?

[LeadingEdge]

With a long build night's work behind us, The FlyingGiants Desert Aircraft
DA-85 powered beast is ready for test flight! Tomorrow, The California FG Staff
will be heading out to The Riverside Club to wring this baby out!

We have an incredibly busy week ahead of us including THE FLYINGGIANTS
SAINT LOUIS HUCKFEST!, and we wanted to bring back the first flight reports
back to our members as quickly as possible. Huckmaster Jeff Szueber will be
the star of our show, and we'll have full video, EagleTree logging graphs, and
post-mortem flight debriefs throughout the weekend.

Stay tuned to FG for the latest breaking news regarding this awesome new
product from DA!

This is the final photo of the evening of the install, complete with a KILLER 27/12TH.

Please post any questions you have, and we'll do our best to answer 'em.
The fine folks at DA will be in to support this thread as well.

Enjoy!

~FlyingGiants Staff

[Howie]

WHAT! No Canister muffler??? Biff's not going to be happy!

[TazmanianDevil]

Wow, that is a beautiful engine!