Hangar 9 Alpha 40 Trainer… Experiences good and bad.

At my local RC Club we have had several of the Alpha 40 RTF trainers (the orange model) used by students while learning to fly.  In general, these have been excellent flying airplanes.  Stable and well behaved with the included Evolution engine providing more than adequate power.  We usually ended up swapping the three blade prop for a 2 blade, especially if the 3 blade got broken.  Two blades are more efficient and much more widely available.  We would often eventually remove some of the limiters on the motor (needle valve collars) to get more power out of the engine as well.  After all, to much power is almost enough!  Generally these planes have been pretty trouble free and fly well.

Given all of this, when one of our younger members lost his Alpha to a battery problem another was purchased and the job of assembly was mine.  We presumed the new ARF would fly similar to the old RTF… especially using the same motor, servos etc…  Pretty much everything except the battery, switch and one of the servos survived and was moved to the new plane.  As I was building the new airplane I noticed they had redesigned the firewall and added a bottom hatch (surely a side effect of adding an electric power option, which I applaud).

Unfortunately I also noticed a few issues I was not particularly happy about.  First, the throttle rod routing is not ideal.  This is not the first plane I’ve seen with this problem so I did a bit of creative warping and rigged up something that was workable.  I’d recommend skipping installing the rod and substituting a cable type linkage to make the throttle linkage work with much less binding.  Likewise, the nose steering rod binds.  For this one it appears to be a problem with the routing of the rod combined with the flat ground on the steering strut and the straight steering arm.  As the arm rotates back toward the firewall, the wire binds against the edge of the guide and puts a lot of stress on the rudder servo.  If you position everything perfectly and limit the end points during your radio setup you can get a workable setup.  Luckily, there really isn’t much travel needed on either the rudder or the nose wheel so I managed but this seems like a poor design to expect a beginner to be able to successfully handle.

Another of our members suggested the use of an offset steering arm might accomplish the relief of this stress and allow for more travel.  I think it is certainly worth trying.  In the meantime we had a workable arrangement if not ideal.  Onward to the test flights.

A bit of tweaking, a balance check and the usual post build checks and we made a few test flights.  At that point, we started to notice a pattern of difficult takeoffs followed by lots of trim inputs, etc…  This was not good.  We couldn’t hand this ill behaving plane to our young member and expect good results.  He was still just getting comfortable flying without an instructor and not ready to handle this ill behaved ship.

It took a lot of left rudder to keep the plane flying straight down the runway and if it was trimmed for straight takeoff rolls the plane would constantly turn in the air and had to be re-trimmed for straight and level flight.  We tried many different adjustments, re-aligning the front wheel and rudder several times, trying various landing gear bends, insuring the wing was centered etc… but we could not keep the plane from at least often, if not always, veering sharply right when it was near rotation speed.  We also tried to add some lead to the left wingtip after noticing the right main wheel often stayed on the ground longer than anything else which seemed to help.

At that point we tried another Alpha wing which did NOT resolve the issue entirely even though after it was removed it was proven the first wing was very off balance… being heavy on the right wingtip.  This is an ongoing investigation at this point but after spending 3 hours working with 2 other RC pilots with probably 50 years RC experience between us… it makes me wonder what would cause this plane to act so oddly during takeoff.  I don’t believe the new Alpha ARF has this problem generically… it’s just this particular model that is vexing us I’m sure.  Once we figure it out… or get tired of this and just move on to another trainer… I’ll post an update.

For now, I can honestly say the Alpha 40 ARF doesn’t seem to be quite as good as the predecessor RTF model but is still a pretty good deal for the price and the only downsides should be readily avoidable if you know what to watch out for and spend just a few extra dollars on a throttle cable and a different steering arm!  Hopefully with these tweaks you can assemble a good flying airplane suitable for a beginner and still enjoyed by those of who have been flying for 15 years or more.

 

Xion Wing Lock – Pt 3 – Can’t recommend

After another couple flights on my Wild Hare Slick on Saturday I have lost a second wing lock.  Once again, no harm as I have clips on my anti-rotation pins and they once again stopped the wing from sliding out far enough to cause any issues.  I had the wing locks very snug and I believe installed these correctly so I can’t account for how they managed to exit the airplane.

Because of this, I can’t recommend this system.  While I love the idea of quick connect and disconnect and somewhat easier installation than the nylon bolts I was using…. I can’t positively identify why mine have now twice been lost in flight.  If these had been the only thing holding on my wings I would have trashed an airplane… twice now.

I’ll have noticed the studs from Xion seem very sloppy in the blinds that are in my wing so maybe this is somehow contributing to the problem.  Is this just a case of cheap blinds with to much play in them?  I don’t know but I’m done risking my plane to find out.  If you use these successfully I’d love to hear about what you did to make them work but I’m done with them for now.

For my earlier posts on this item, please see:

Part 2

and

Part 1

 

 

Xion Wing Lock – Pt. 2

Last weekend at the field during the IMAC contest I lost one of the cams and the washer on the port wing of my Slick.  No big deal really… I have clips on my anti rotation pins on each wing so I needed a click of aileron trim and all was fine.  After the flight when I went looking for the reason I spotted the wing gap and on investigation found that the cam and washer were gone and the stud had rotated out a bit.  I didn’t have my spare so that wing went back to the nylon bolt for the rest of the day.

So what happened?  While it is impossible to tell for sure, I believe the problem was rooted in not seating the wing down snug against the body.  So when I locked the cam down it pulled the wing in a bit but not enough to put pressure against the cam and therefore with some vibration the cam escaped.  Maybe the stud rotated enough to further loosen as well.  Possibly contributing to this is that I have not glued the washers down inside the body either… perhaps if I had the slack in the system would not have been enough to allow the cam to escape??

The only other issue I can see is that perhaps the stud managed to pull out of the blind nut embedded in the wing root.  I am really not fond of blind nuts in any case.  I find most of them to be ill fitting/loose.  When used in conjunction with a standard bolt there just seems to be a lot of play and I have seen a bolt manage to walk itself out a thread or two before without rotating at all because of vibration and slop.

I have continued to use the system through another 6 flights or so and so far have not had a sign of any movement.  I may add some plumbers tape to the studs to cut down on “rattle” between the studs and the blind nuts before my next trip to the field.  Otherwise I will keep with it and see how it goes.

(Don’t recommend these anymore… see part 3)

New Gadget – Xion Wing Lock System

While walking the aisles at the Weak Signals show in Toledo I ran across the Xion Wing Lock System.  These little gadgets are an interesting alternative to 1/4-20 or 6mm wing bolts that screw into the wing root to hold the wings in place on your favorite aerobatic aircraft.  After watching the demo a couple times and recalling the times I’ve found a wing bolt rolling around in the bottom of the plane or struggled to get a socket wrench or screwdriver onto the wing bolts… I thought these might be an interesting alternative.  So wallet a bit lighter, I pocketed two sets of these and moved on with high hopes.  Here’s a stock image of the Wing Lock system from the Redwing RC website.

http://www.redwingrc.com/images/xion_wing_lock_wing_bolt.jpg

As you can see, the wing lock system consists of a stud that threads into the wing root, a rubber washer that installs onto the stud inside your aircraft body and the lever/cam lock that slots into the stud and, when rotated 90 degrees to flat against the body of the aircraft, tightens the connection.  Here is an example installed in my aircraft.

 

photo 2

To get to this point you have to drill out the wing bolt holes a bit and screw the studs into the wings.  (The enlarged hole is only 1/8″ or less larger so going back to 1/4″ bolts is not a problem if you later decide these are not for you.)

Now I will be the first to admit that I’m a bit of a gadget fan when it comes to RC.  I like trying out the new doodads and these are no exception.  I must also say that my current system of nylon bolts backed up by clips in the anti-rotation pins works excellently… So why the new system?

In addition to the allure of getting to play with a new gadget, I have always had trouble reaching the wing bolts inside my airframe.  The bolts are close up behind the main wing tube and with my large hands it requires a screwdriver to get the bolts inserted and tightened.  I was hoping that these wing locks would resolve that issue.  They looked very easy to connect at the show…

So are these the ultimate RC gadget?  Will they keep your wings firmly in place? Are they the solution to my wing bolt woes?  Here’s my experience so far.

I flew 3 times today after installing the Wing Lock system.  The wings stayed firmly in place and the wing locks didn’t seem to have budged… Not the slightest movement or loosening was apparent.  There’s seems to be a lot of questions out there on the web about whether these things will hold.  I’d have to say I’m no longer concerned about that.  Based on my experience, I’d have to say that they do work as advertised in this regard.  In addition the craftsmanship seems to be excellent and they are very light, which is always a plus.

The major selling point on these seems to be that they make wing assembly quicker and easier.  In my particular application it’s a bit difficult to reach the assembly point inside the aircraft body and at first blush this system didn’t make that any easier.  My fingers still don’t reach there easily and I can drop these into the bowels of the airframe just as I did the wing bolts!  I must say they are significantly faster (no 15 turns of a screwdriver in a tight area) so in that regard the system works as claimed.  I do appreciate this because it can be a back breaker at times to reach the wing bolts.  Using the wing locks doesn’t change how hard it is to reach this part of the airplane but I can’t blame the Xion folks for how my airframe is laid out and they do go together faster than my old wing bolts so less time spent hunched over is an improvement.

Not much can be done about where I have to reach to attach my wings and where things land when you drop them inside this airframe…. so I’m going to try tethering the cam locks to help limit the number of times I have to fish out the parts!  Maybe by doing that and with a bit more practice installing the cam levers I can maximize the benefit of the system.

Overall I like the Xion system and they certainly make assembly of my aircraft a bit quicker.  It’s always difficult to justify spending $15-20 when you have something that works already in place but I don’t regret spending the money for the Wing Locks.  I think I’ll keep using them and will update with any new revelations or changes I make.  So far I’m still thinking these are pretty cool.

(Don’t recommend these anymore… see Part 3)