I'm wondering if anyone following this thread has experience converting a pylon free flight ( am considering the old Satellite 1000) to radio assist. Would really like to get your advice on making the modification, and if you thought it was a worthwhile project.

We are in good company. I'm looking at a kit for a 1/2A model that I have as a possible conversion to Speed 400 electric.

What I'm considering is to make it pretty much as per plan but I'm going to go for a fat symetrical airfoil shaped pylon to house a good part of the radio gear and motor batteries.

The CG will be kept the same as per plan and I'll go for a rather narrow 10% wide elevator with limited movement to ensure I don't run into too much elevator sensitivity. The fin and rudder will be split at the 50-50 line for good turn response in the glide.

If you're going gas for a "scale" like vertical pattern you'll want to use dual rates on the fin and rudder and run pretty much the minimum movement during the power pattern. The speed they get in the pattern coupled with all that dihedral makes almost any amount of control input TOOOOOOO much. Actually it may be best to set it up for an unmolested power pattern and then kill the engine with the radio and THEN take over flight control after the roll out. Not many of the free flight models of the Satelite type construction take kindly to power pattern aerobatics so you'll want to beef it up considerably or ensure that it doesn't get too squirlly in the power pattern.

Of course with all the raw power from a speed 400 electric I won't have this problem...

The kit I'm thinking of converting is an Air Express by Phil Hainer. He's a well known local modeler here on the west coast that passed away a couple of years back. He marketed his own hand cut kits for a few years and the Air Express was the NFFS model of the year a while back.

I'd love to see a 40 to 60 sized Rossi on a 1000 with gear. Even the hotshot jet jocks would stop to watch THAT one go up....

BMatthews,

Thanks for the reply! Have to admit that throughout a youth misspent flying control line and nearly 30 years with RC I've never laid eyes on a pylon much less seen one fly. Well, I did see one on video tape. Outrageous takeoff. Anyway, figured that if I was ever going to see one fly, I'd have to build and launch it.
Youv'e given this pylon conversion some thought so if you don't mind I'd sure like to ask a few questions.
Noted that you are going to retain the original CG. I'm assuming that it is located in an aft position, as seems to be the practice of the pylon designers. What's the idea here? The Satellite's CG is located about 80% to the rear ??? You think that ought to remain the same?
I'm taking to heart your plan to limit elevator area to about 10%. What would you think of limiting the surface to one side of the horizontal and mounting it inboard to help limit
any roll tendency, saving the weight of a cross-over rod, material and hinges. Minor, but if you don't ask, you don't learn, right?
Also, what do you think about installing spoilerons to handle the steering? That is, sans rudder. The purpose is to get the plane back to the field and enjoy some degree of control in flight. The terrain is pretty rugged here, if a plane lands off-field you can pretty much write it off. Anyway, just don't know what to expect nature of a turn would be. If you could even call it a turn.
Am assuming that your Air Express has a "modern" wing plan form. Do you see any advantage to that vs. the older eliptical shape?
Going to leave it at that. Thanks again for a helpful response.

ddubya

Free flighters go the extra mile in south Texas too.... they just return scratched, bruised, and probably snake bit... without their planes.

You definetley want to stick with the stock CG, or at least don't go more than 5% forward from that point. You'll thank me during the power pattern if you use a strong engine for a typical Satelite like climb. Any further forward and it'll want to loop over and kiss its own tail. And as I suggested almost any amount of control at those speeds is way too much. At least with an RC carb you could sneak up on the climb trim. Actually forget I suggested the 5% forward option. Under power it'll still want to loop over strongly and with the CG being that far back the elevator response is touchy as you would expect. To offer some insight stab shims of only 1/32 can be the difference between a crash and a good climb in trimming these types of models.

The single sided elevator will work fine for the sort of pilot assisted recovery you describe. It's been done successfully before. I also know some guys that fly 1/2A Texaco models with this arrangement and it only needs very minor rudder compensations that you can only recognise after flying in lots of conditions and many flights.

You're on virgin ground with the spoileron system. But frankly for this size model I'd suggest you stick with fin and rudder. I'd think about mounting the two servos in the fuselage just behind the pylon and use kevlar pull-pull links for both the rudder and stab. Keep the servos in line and be sure to use spruce longerons along that area and back to about 18 inches behind the pylon to compensate for weakening the fuselage spine that close to the load center with the openings. That would let you make the tail removeable very easily for transport. If you go for a typical Satelite climb you won't need to worry about oil as the run will only be about 20 to 25 seconds after release.

Ideally you want to use a combo of balance point shifts, rudder and elevator trim and engine thrust offseting to achieve a full power climb that goes straight up with about 2 to 2/12 turns in the climb. If it tries to loop over during this corkscrew climb then move the balance back a trifle and retrim the elevator until it stays vertical but in the corkscrew turn without rotating past vertical. That's the short version but it should help you get going. Use the fast idle to gain 50 or so feet and then feed in power until you hit the right pattern under full throttle or it diverges from what you want. Adjust trims, balance or engine thrust as required and try again until it's right. And set it up for a right corkscrew under power and an open 100 to 120 foot circle under glide. Use the controls as required to intterupt the path to direct or recover. This all sounds like a lot of work but if you make the engine mount to allow for adjustments then it's really not as bad as you think. And think of the aerodynamics you'll learn.

And just imagine the shocked look in your buddy's faces when you launch the model under full power with the TX sitting on the ground beside you. After a scorching 20 to 25 second climb and with the model a dot under the clouds you calmly reach down and with one finger non chalantly flick the throttle control to "off". Up there the model pauses and flips into a floating glide to circle serenly overhead like a hunting hawk.......

Excuse me, I 'm getting all goose bumpy just thinking about it....

Bmatthews,

all sounds like sage advise. How in the world did fliers manage to get these birds trimmed for successful flight. You would think that one miss-trimmed launch, and you have a pile of rubbish...in VERY short order.
I've been spending some time trying to find out the classes and engine sizes for this type model and haven't found a single article in recent issues of MODEL AVIATION. What happened? Surely there is some remaining Pylon activity. At any rate, am wondering what the span is for a .25 to .30 engine. Any idea?

ddubya

And that is very often what did happen I know...hence one of the reasons for my dislike of anything smelly

Try taking a look for the vintage (SAM Society of Antique Modellers) groups in the US on the net - the rules still seem to differ from one country to another so there is little future in promoting the NZ rules here.

From one antique modeller to another...

probligo,

thanks, I'll check the SAM site out.

When converting FF to RC, a good rule of thumb is to only build in half the specified amount of dihedral. Otherwise you will find the roll response is way too touchy as soon as you move the rudder, especially if you are retaining the rearward CG.

I recall some people preferred using the radio gear purely as an assist for models like these, so they only had two channels - one was an engine cutoff by servo rather than by timer, and the other was a rudder about the size of a trim tab. The only control they wanted was to stop the engine, and to keep the plane more or less over their flying site. It was a matter of pride that they could complete 99% of the flight without picking up the transmitter

THANKS STEVE,

I'm taking note of all these tips.

As probligo said it "And that is very often what did happen". It takes LOTS of short engine runs and study followed by learned bits of minor trim changes to set up a high powered free flight model. And Disaster is a companion constantly waiting at your shoulder during the testing.

Steve-kerry has some good points but I don't think you need to reduce the dihedral as long as you limit the rudder throw and size. Besides, the reduced dihedral will ruin the roll out if you choose to follow the "minimal disturbance" form of "radio interferance". You'll need a faithful free flight planform for unassisted climbs and rollouts.

As far as engine size to model size goes I suspect for a 25 to 30 you'll want a 600 or so sq inch wing area. The rest will scale apporpriatley with the span coming in at around 55 to 60 inches or so. But this is assuming you chose a HOT engine. The Satelite 1000's normally fly with a formula 1 Torp 40, or Nelson 40 as a minimum. Rossi 60's running on pen bladders (aka speed engines) are not unheard of either although these hotter engines also show up on 1100 to 1200 sq inch monsters as well.

That's true, I was thinking more of converting a sport FF to RC for everyday flying. If you want to take the "minimal interference" route, leave the airframe alone apart from a small rudder tab. The less we interfere, the better they fly

Thanks you all,
for the ideas and tips. I see now why certain things were designed the way they were. I've changed my mind and plan to reduce the 1000 inch craft down to 60" span. Seems more prudent to get the kinks worked out with a smaller plane, then do the monster. Will go for minimum control surfaces and make as few concessions to radio gear as possible. Thanks again!