Cirrus Micro Joule Flight Packs
 

Hi,

I'm using one of the new improved Cirrus Micro Joule Flight Packs to convert an electric free-flight plane to R/C.

These new Micro Joule (MJ) components are perhaps the smallest in micro-flight technology ever produced for easy plug-n-play usage.

The MJ servos weigh about 0.1oz each and the 0.1oz MJ receiver is a single conversion narrow band type that automatically detects the modulation shift for use with Futaba, Hitec, or JR transmitters.

The setups below show a full-house 4-channel system using the 0.1oz, 5amp ESC for 2-cell Lithium operation and a second setup for lighter rudder/elevator planes using a single Lithium cell ESC that can also handle 5amps but weighs only 0.07oz.

The full-house setup would be great for an indoor aerobatic, 3D, or scale warbird model. The lighter single cell setup with only two servos would make a great flight pack for a trainer with rudder/elevator or aileron/elevator controls. Of course, either setup can use the one-cell or two-cell ESC option depending upon the plane size and desired motor power.

I have tested both setups on the bench and found no servo jittering that plagued the first release product. The pre-wired (and keyed) connectors really made things easier to assemble and remove. Both ESC versions have a safety arming procedure that requires the throttle stick to move up to full and back to off again before powering the motor.

All these little added touches reveal an excellent design strategy by Cirrus!

RE: Cirrus Micro Joule Flight Packs
 

I asked myself, "What is the advantage of using the Cirrus Micro Joule Flight Pack?", since the cost of these incredibly small components is greater than other larger flight packs that weigh more.

The answer is that several things are an advantage with this new micro-sized flight pack. In the past, micro-flight has been a complex and specialized area of R/C. Many different types of knowledge and skill sets were needed to fly a model that weighed only a few ounces or less. With the Cirrus MJ Flight Pack, I will demonstrate just how easy it is to convert an inexpensive free-flight model to R/C. This type of project always gets me excited as it brings back memories of wishing this were possible when I was just a kid.

My conversion project will feature the [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXRX21&P=7]Hobbico FlyZone Classic Cruiser[/link] which is under $20 at the local hobby shop or on-line. The 21.5oz Cub-like design looks cute and weighs only 3.0oz RTF stock.

RE: Cirrus Micro Joule Flight Packs
 

The first step was to determine the stock CG and then mark it on the wing bottom. It was just behind the plastic wing strut.

RE: Cirrus Micro Joule Flight Packs
 

I cut out the 2-cell circuit board from the belly of the plane. It weighed 0.6oz.

I then tested the stock motor on a variable DC supply. At 2.0v it was drawing about 3amps so I figured that my single Kokam 340mAh cell was a fair match since it can deliver up to 6amps continuous at about 3.6v.

Typically, these stock free-flight motors are very current hungry but I wanted to try using it to help simplify the conversion.

Here is a list of some component weights:
[ul][*] Stock Hobbico Classic Cruiser RTF = 3.0oz[*] Stock 2-cell Charging Board (removed) = 0.6oz[*] Stock Landing Gear = 0.1oz[*] 1-cell Kokam 340mAh pack = 0.4oz[*] MJ Receiver, Antenna wire, 2 servos, ESC w/wire = 0.4oz
[/ul]

RE: Cirrus Micro Joule Flight Packs
 

The control surfaces were cut out next. Both the elevator and rudder have lines in the molding for easy tracing with a razor knife. I used a straight edge and a fresh blade to ensure a clean cut.

The two elevator halves were then connected with a thin metal joiner that I epoxied into the "V" area between the halves. It is best to assemble this on a flat surface. I sanded the wire first for a better hold and then glued it onto the foam elevator halves using 5-minute epoxy.

I also sanded a 45 degree angle into both the elevator and rudder surfaces where they would be taped back onto the plane. This helps them to swivel properly.

RE: Cirrus Micro Joule Flight Packs
 

Before attaching the elevator assembly, you must first cut out a small section of foam to allow for a proper swivel up and down. A 30 degree swing in either direction is plenty since it is a large elevator.

I taped my elevator in place using four pieces of clear cellophane tape.

RE: Cirrus Micro Joule Flight Packs
 

To mount the rudder, I used a combination of tape and hinge material. The hinge material on the bottom of the rudder was glued into pre-cut slots using white craft glue. The hinge material provides a stronger support for the rudder for adding a steerable tailwheel (if desired) and for just keeping the rudder in place. Alternatively, a second piece of tape here would work fine too.

My finished tail looked great! Both control surfaces could easily swivel 30 degrees in either direction.

RE: Cirrus Micro Joule Flight Packs
 

Greg,

In post #6, I notice there is a lot of bow in the horizontal elevator. Running a rounded tool along the hinge line and inletting a piece of CF rod in there will straighten that out for smoother control operation and it will also allow for figure '8' hinges as an option to tape...

RE: Cirrus Micro Joule Flight Packs
 

Hey Greg, thanks for the initial review of this system. I've been eyeing it, wondering whether to get it or not. I've got the RFFS setup, but it's SO dainty, and I'm not an actuator fan (more to the point, I'm too rough on them [:o] )

I may get one of these soon.


Thanks!

phil in austin

RE: Cirrus Micro Joule Flight Packs
 

Whats better, this system or that RFFS100 thing? I'd like to try converting some old peanut scales and free flights.

RE: Cirrus Micro Joule Flight Packs
 

TommyGun,

Which is better - an apple or an orange??? Both systems have their advantages.

The RFFS was the first plug-n-play micro system that opened up this area of modeling to the masses, but their edge is rapidly eroding in the face of the developments in minature systems. I was an earliy RFFS adopter, and had giant fun with them for a couple of years. They suited me just fine, and I was willing to put up with the wide-band nature of them. I don't fly a very crowded fields often, and have had few interference issues with them, but I did get shot down at a club field once while I was demonstrating the micros when about 20 TXs got turned on while I was in the air (very embarassing). I learned how to make friction-free hinges, keep everything perfectlyaligned, etc., and I will always have some of these systems ready to fly. They are very simple, light, rugged and, for my purposes, well suited to my needs. I have started lightening them up and can put together a 3-channel system that weighs as little as 3.7 grams with RX and ESC and 2 actuators, and 5 grams with a pager motor. This is good for some lighter and smaller area peanuts.

That being said, I have started using the MJ and other new systems (like the JMP or Penta systems, Falcon servos). The weights of these is more, but control is more positive, especially in higher speed models. My last few planes have been servo-driven, and I am very pleased with the results. I have used them in 11 3/4" to 18" sticka-and-tissue models, and the weights are comparable to the stock RFFS w/2 BSD actuators. Installation is no harder than the RFFS with actuators, and I can fly them at club events without worry. The latest of these is peanut Pitts Special from 1972. AUW weigh will be ~ 1 ounce.

The first MJs were very trouble-prone, but the manufacturer has taken great pains to correct the early systems short comings. The products are still being refined and are constantly improving, and the ones I have now are quite acceptable. Hobby People (the LHS) has an unsurpassed customer service policy, and they are quite happy to swap out any funky components. I'd say it was a 'no questions asked' policy, but they do ask questions. The questions are what failed and under what circumstances. They pass the answers along to the developers for further R&D, and the early problems they have discovered and suggestions we've put forth are used to improve the product. Very professional, in my opinion.

You can always tell the pioneers - they're the ones with the arrows in their backs. The RFFS was over taken by the MJs, and the JMP and Pentas are taking aim at them. I have used all of these, and they are all fine systems. They have come so far that a comparison is no longer a defect list of each system, and has become a positive comparison. The hardest part is deciding what gear fits your purposes best. Lighter weight, built-in or external ESCs, need to run 1 or more cells, need for 3, 4 or 5 channels - these questions really determine which is 'best'.

In short (I know, too late!), they will all do the job of running a peanut model, and the 'best' one is the one you put in there and go fly with. If you subscribe to RCMF, all the gear has been tested thoroughly and well documented. Much of this has also been examined in the RCGroup's 'Inside Story' columns.

RE: Cirrus Micro Joule Flight Packs
 

Yeah, what Mike said!


phil in austin (who'll be getting a joule system soon enough)

RE: Cirrus Micro Joule Flight Packs
 

[quote]ORIGINAL: Mike Taylor

The RFFS was over taken by the MJs, and the JMP and Pentas are taking aim at them.




Thanks for the reply Mike, this certainly helps. I have to ask, what is a JMP or a Penta, and where can you buy them? How much do they cost, and what makes them better than the Cirrus system? I'm interested in full proportional units only.

RE: Cirrus Micro Joule Flight Packs
 

Tommy, this thread has gone way off topic. It isn't polite to hijack a detailed build out with OT subject matter. Sorry Gordon. I'll start a new thread.

RE: Cirrus Micro Joule Flight Packs
 

My apologies.

RE: Cirrus Micro Joule Flight Packs
 

Hi Mike,

You are right about the bowing on the elevator but it isn't a problem for the MJ servos. They are much stronger than the magnetic actuators that have been plagued with hinge line tension issues. The stronger MJ servos allow you to be sloppy (much like a novice would) and not have any ill effect. This is a good attribute of the MJ flight pack for entry-level micro-flight enthusiasts.

It's good to see you back here handling micro-flight questions. :)

Phil,

I understand your pain. I have built many micro-flight projects, and, although the MJ Flight Pack is not the lightest available, it is the easiest matched set of plug-n-play components I have ever used.

For actuator setups, my favorites are the self-aligning Selman magnetic actuators and a JMP narrowband receiver. When flying indoors in groups, the DWE RFFS100 has interference problems (sometimes) but they usually work fine when flying alone in your backyard.

RE: Cirrus Micro Joule Flight Packs
 

I choose to mount my MJ receiver and servos in a position that was easy to install and also provided access for "show and tell". Most of the local area flying clubs have never seen this technology before so they are usually loaded with questions after I fly a 3oz plane outdoors.

The receiver and crystal will later be protected with foam and tape. The servos will need only short control rod runs to the elevator and rudder. For entry-level simplicity, I will be using thin metal rods instead of carbon fiber. More experience micro-flight enthusiasts can use alternate mounting positions, techniques, and materials.

After cutting slots into the foam, the servos are simply held in place with clear cellophane tape. I glued a balsa piece inside the fuselage to create a shelf for the receiver to sit in. It is held in place with double-sided tape. The crystal will later be bent 90 degrees and held against the fuselage with clear tape. Another photo will show the receiver sides protected by foam slices cut for the servo bays.

RE: Cirrus Micro Joule Flight Packs
 

The stock power system has plenty of built-in down thrust. I was excited to be able to use the stock power system since it greatly simplifies the conversion and reduces cost.

Although a direct drive motor uses much more current than a geared setup, the inefficiency is somewhat negated by the Kokam 340mAh cell. It will be interesting to see how much throttle is needed to maintain flight.

RE: Cirrus Micro Joule Flight Packs
 

I protected the receiver with some foam sides and taped the bent over crystal with clear tape. Additional protection is provided by the stock landing gear. All the components could still be seen on my conversion for showing it off at local events.

Since the servos were a bit aft, I needed to place my Lithium cell up front under the nose to balance the plane. I cut a slot into the foam and the cell just presses in place.

RE: Cirrus Micro Joule Flight Packs
 

My converted Hobbico Classic Cruiser was Ready-To-Fly (RTF) at only 3.3oz or 3.2oz without the landing gear.

The Cirrus Micro Joule servos easily controlled the elevator and rudder in both directions. My initial ground testing showed no sign of jitter or interference.

I can't wait to test fly it!

RE: Cirrus Micro Joule Flight Packs
 

As I wait for a calm day to test fly my converted model, it stores safely back in the original box with the wing and landing gear removed. It can stay in my car until needed.

RE: Cirrus Micro Joule Flight Packs
 

how much does all that cost including the Tx? i want to fly but so far have been totally unsucsessful.(stoopid z plane).

RE: Cirrus Micro Joule Flight Packs
 

The Cirrus [link=http://www.hobbypeople.net/gallery/443414.asp]Micro Joule Flight Pack[/link] is around $150 at Hobby People. I am not certain is different versions exist yet for a single or multiple Lithium cell project.

All the components can be purchased seperately to suit your needs.

RE: Cirrus Micro Joule Flight Packs
 

My first test flight was a re-learning experience. :)

I had forgotten that these electric free-flight planes are designed for lift. By the time I got it under control, I had added two Quarters (0.4oz) to my nose and drained the battery. The extra weight equalled my single Kokam cell pack.

Upon inspection, I realized that not only was the stock CG meant to be tail heavy, but the wing incidence did not match the horizontal stabilizer.

Fortunitly, these changes are easily made. I added a 1/32" balsa wedge to the aft end of my wing saddle so that the angle now matched the tail. The stock offset is not needed on an R/C model as you control the climb with the elevator. Note: After the second set of test flights, it was determined that the 1/32" balsa wedge was not needed.

It was time to remove the two Quarters and move my components forward. I easily cut around the Cirrus MJ receiver and removed the tape from the two servos. Everything was glued back in place resulting in a much lighter tail section.

RE: Cirrus Micro Joule Flight Packs
 

To extend the existing control rods, I cut them in half and CAed the wires inside a thin plastic tube. The servo arm and tail surface alignment was made quickly before the CA had a chance to set.