Turnigy powered Mustang BL

The Parkzone Mustang BL is a great looking model.  I resisted the temptation to buy one right off the bat, hoping that a small wait would result in some aftermarket parts and a proven formula to build one inexpensively.

I’m not breaking any new ground here, just condensing information I found on RCGroups and what I considered the best aftermarket mount.  There is a master thread at RCGroups that you should absolutely look through if you are considering a build.

The best value is to buy the parts as the complete airframe, the part number is PKZ1870.  I paid $79.99 for mine from Horizon, and note that when you ship there is typically an oversize charge.  The box is HUGE!  Still, you save quite a few bucks over buying the pieces individually, and you also get some labor items done for you, like cowl fitting, control horns, and decals.

The genesis of this idea was discovering the way-cool mount that Customrcparts.com makes.  I opted for the venerable Turnigy 35-36C, because I like them, and also because I had a good one on the bench

The Turnigy Plush 40 or any 40A speed controller will work fine, as long as it is slim enough to fit in the nose of the airplane.  HXT-900 servos fit right in the pockets and are dirt cheap – to date, we’ve never seen one fail in service under normal use, and they are plenty fast.

The Customrc mount is great.  It goes right in, and you can use the stock spinner and prop with the Turnigy motor.  Everything just lines up
Note – You can’t use APC props with this setup, they don’t fit, and you would need an aftermarket 2.25″ spinner.

I noticed a lot of little niceties in the parts – there are channels for servo wires in convenient places, a nice tray for your RX, and the aforementioned pocket for the ESC. 

I opted to do the optional rudder sutup, which was quick and easy.  All the parts come in the airframe kit, and I can’t think why you would not do it for the price of another HXT-900.

I used Hobbycity 3S 1850 40Cbatteries, because they fit the pocket so well.  There are a lot of well-documented mods on RCGroups that allow you to use 2100′s quite easily, I just happened to have these batteries on hand.

I used the stock 9×6 for the maiden flight, which was a joy.  It’s got great, forgiving handling, feels very nimble, and does the full suite of aerobatics with ease.  I didn’t take any measurements on the maiden flight, but for the next flight I installed a Master Airscrew 10×8, and went to town.

Awesome.  We got two confirmed radar passes at 69mph, and you can go 5 minutes at triple latte on the 1850 and still have a little puff to get home.   I didn’t get an Eagletree reading today, but we registered 41.6Ap 476Wp in static testing with the 10×8.  I bet I’ll be able to tune for a little more speed once I get some Eagletree data.

The best thing about this is the fact that you can put one in the air for about $175, but you get some substantial upgrades like more horsepower and the aluminum mount.  It’s a blast to fly, and I’m looking forward to further mods like retractable landing gear, and flaps.

My new favorite daily driver

Overall, it’s clear that Parkzone is not resting on their previous success.  The overall design and flight characteristics of this model are top notch at any price, and using the aftermarket parts, you get a chance to customize your plane with the servos and powertrain you prefer.

The Parkzone F-27 Stryker is an amazing airplane, especially at the price.

The inherent stability and good low-speed manners of this model break the traditional idea that fast pushers need to behave like lawn darts.

I build my first Stryker from parts last year, employing the E-Flite Six 2700kv motor and 3s high-capacity Rhino batteries.  With a 6×4, we were seeing 85-90mph reliably in radar passes, and the model handled great.

I started reading about the EFL Six, and learned that you can push a lot more than the recommended max of 42 amps.  I decided to order up some 4S Rhino batteries, and build a new Stryker.  I used an Align 450 K10175A heat sink, and decided to try one of the new Turnigy 85A ESC’s that have a built-in heatsink.  I also installed a motor temp probe for the Eagletree logger.

The first flight was uneventful, until I really started pushing up the speeds.  We saw a couple of 85+ mph passes, and whenever I started flying faster than that, I started noticing some serious problems steering the aircraft.   We decided that I was going to need to beef up the airframe and the elevons in specific before flying it any more.

I beefed up the structure with carbon fiber rod, and day-glo duct tape.  I applied CF tape and thinned epoxy to the underside of the elevons, which helped quite a bit.

At this point I also got a little reckless, and installed a new prop.  I had been running with a 6×4, and decided to put a 6×5.5 on there without thinking about how much of an increase that was. 

….  and it proved to be too much.

The model flew much better with the stiffer airframe, and spent the first part of the flight just getting used to it.  Finally, I decided to ‘give it the berries’, and see how we fared.

I wasn’t sure, but I thought I saw a little smoke trail on that climb.   I did a nice long power off glide, pretty much assuming that the motor was fried.  When I throttled up again, I was astonished to hear the motor spin up.  I decided that I must have been seeing things, and did another pass.

This time the smoke trail was unmistakable.   I spun it around, power off, and landed.   The motor was crispy critters, you could smell it a mile away and it was actually melting the plastic motor mount. 

In reviewing the data, it looks like I tried to push 96 amps through the motor, and the sky-writing was predictable at that current.

Eagletree graph, illustrating abuse

 I really should have been more cautious, we live and learn.

I got one of Custom RC’sStryker modular motor mounts, and this is a really nice looking part.  It is available with a 28-30mm head, a 36mm head and also a special 36mm unit designed for Mega motors.   I plan to use one of Hobbycity’s 36mm inrunners, although getting the model to CG will probably be a challenge.

More news as it becomes available,

- Eli

UPDATE 3/22/2010 -

First, a word on Custom RC.  Not only was the Stryker motor mount a joy to install and look at, these are seriously nice people to boot.    I guess they dropped the price on the Stryker motor mount by $10 recently, and decided to issue credits to customers who had recently purchased at the old, higher rate. 

Nobody does stuff like this anymore, and my hat is off to Gary and his folks. 

The Hobbycity 36mm motorwas heavy, but it balanced – Now that I have the motor in hand I realize it’s a car motor – I took it out with a Graupner 6×6 prop installed, and the thing flew great until about 100mph again, at which time it started corkscrewing all over the place.  I’ve decided that I’m going to glass up a new airframe before going any further, this airframe is trashed.

- Eli

Waiting for a Horizon Hobby order to arrive

Last week I put in a little stock order at Horizon Hobby.  I order a lot of stuff from them, and after many orders I have a real good idea of how long the shipping interval is from their California Warehouse, and also the Champaign IL location. 

For the last few years it’s been my experience that orders filled from the CA warehouse get to the Bay Area in 2-3 days, tops.  If you want something for the weekend, you order by Tuesday, and you should be set for Friday.  It is important to note that this is when you use the $4.99 shipping option.

Last week, I placed an order on 3/2.  I was really surprised when I did not receive the gear by Friday, and even more surprised when the stuff from IL showed up!

I tracked the package, and noticed that the tracking had been handed over to ‘Mail Innovations’, which is a UPS spin-off.  According to the tracking, the package has been sitting in Petaluma since 3/4.  It arrived in the North Bay 2 days after I ordered it, but’s it’s been sitting since.

I phoned Horizon customer service, and I was really surprised at what I was told, verbatim by the customer service rep:

- The tracking on Mail Innovations items is ‘goofy’, and is not really useful or accurate.  This is known and understood by Horizon.

- The rep recommended that if tracking is important to you, that you should use another method like UPS.

- These Mail Innovations packages can take up to three weeks to deliver.  I asked her to repeat this three times.
When I asked her what I should do if my order did not turn up, she said I should wait another week until Monday, 3/15.

None of this is very good for the Horizon Hobby customer in California.  

We used to be able to spend $5 on shipping and get a small order out to the Bay Area in 2-3 days.

Now, we are told we should wait 2-3 weeks for the same service, and if we don’t like that we should start spending more on shipping.

I’m sure there are extenuating circumstances that caused this, but I would expect some kind of warning from Horizon either as part of the order process, or a bulletin on their website. 

Put plainly, this change, and this poor performance is not what I would have expected from a company like Horizon, especially without notification.  And, when their customer service people tell me that the solution is just to start spending 40% more on shipping, I’m tempted to start shopping around.

**Update 5/2010**

A couple months have gone by since I wrote this, and shipping times have returned to what we always considered normal.  Couple-few days from the CA warehouse, maybe 1 or so more around Xmas.

So, in retrospect I think that the problem I experienced was a fluke.  The subsequent communication problem I had with the service rep at Horizon complicated matters, but who knows, maybe I was a little cranky that day.

Horizon has always been a solid resource for the hobby, and it’s awful nice to have reliable, inexpensive pretty-quick shipping.  Special thanks to Beth at Horizon for getting in touch and making sure that all of my questions or concerns were answered honestly by the right people!

- Eli