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RappyPilot 07-02-2012 12:56 AM

100KM cross country flight.
Hi all

We here in South Africa have an event in December. It is a 100KM cross country flight. Done in one leg.

How it works is you have a truck with someone driving it. And on the back two pilots taking turns flying the plane.

I am quite keen to do this but I have no idea what plane/engine combo would be able to achieve this. I have never been to this event as it is held in a place about 1600KM far from where I live. But thought it would make a nice "holliday" to go do this. BUt as I live so far and have never done it there are not a lot of people to ask for help.

Anyway, I am quite qurious as to what plane and engine combo would work. I was thinking along the lines of using a 40 sized trainer, perhaps build a Sig Kadette LT40 and power it with a SAITO FA56 .... Bulding a plane as opposed to using an ARF would enable me to build a MASSIVE fuel tank into it .... But what size...

What would you guys use to do a 100KM cross country flight in one go?


TFF 07-02-2012 04:57 AM

RE: 100KM cross country flight.
In the 70s , a Goldberg Senior Falcon was flown across the US in a relay. I know there are competitions where the flying is done like a car rally where stages are timed. A gas engined 1/4 scale cub or like seems popular for distance flying.

Gray Beard 07-02-2012 06:43 AM

RE: 100KM cross country flight.
Just recently there was a new record set for long distance RC flight. If you pull it up in the AMA magazine you can read all about it. It was a BIB plane so it could carry a lot of heavy fuel. By recently I mean the last decade, the memory is going a bit, sorry but the AMA folks can find the info for you. I may also be thinking of the one they did using a GPS system in it too?
You know how it goes, they are always setting a record of some type and it mater's not if anyone really cares.
Have fun with it. At one time that was a popular thing to do here in the states too.

bogbeagle 07-02-2012 07:24 AM

RE: 100KM cross country flight.

Is the aim of the event simply to conduct the flight? Or, is it a race, perhaps? Are there parameters defining the size of the models, perhaps? Such issues will determine your choice of model and engine.

More details, please.

In either event, I'd be choosing a model with a high degree of inherent stability, perhaps along vintage lines. I expect that the air gets pretty bumpy once the sun is high. Anyway, you would be well advised to minimise the pilots' workload.

RappyPilot 07-02-2012 09:17 PM

RE: 100KM cross country flight.

It is not a race. Just a flight of a 100KM to see who can actually get to the other side without landing, refueling, crashing. There are no rules as far as the plane is concerned.

And the process is basically a team of 3 people, one person drives a pickup along the route, then there are two pilots taking turns flying/resting.

huck1199 07-02-2012 09:37 PM

RE: 100KM cross country flight.
The LT40 is relatively heavy, I would look for a light and low drag 60 size plane and maybe use a 15cc gas engine.  Most of the arf's are built light as opossed to kit built planes.

JohnBuckner 07-02-2012 10:28 PM

RE: 100KM cross country flight.

JohnBuckner 07-02-2012 10:37 PM

RE: 100KM cross country flight.
This is my most recent cross country ship. It is a Bridi Sun Fly 111 modified considerably for the utilitarian mission Which includes: exposed engine mount and an exposed engine mount, mounted nose wheel as well as exposed surface mount servos. It carries fifty eight ounces of fuel in three tanks plumbed in tandem for better than two and half hours at cruse speed or about forty five mph. The engine is an OS .70FS.

Last year I had to cancil my river XC which was 62 measured miles as the colorado river runs due to my poor health and the cost of hiring two boats. My personal best on wheels was 75 miles along old Route 66 from my home field here in Kingman to Seligman Az.


bogbeagle 07-02-2012 11:45 PM

RE: 100KM cross country flight.
My thoughts are that there won't be a need for speed ... you only need to fly as fast as the road vehicle + a margin in case of headwind. I'd imagine that your road vehicle won't be belting along too quickly, esp with two people loose on the flatbed.

So, a lightly-loaded, clean design, hand-launch, small engine, lots of stability. Powered glider would fit the bill. Maybe a .52-sized four-stroke engine, pumped would be advantageous. Need a good flight-battery.

It's amazing what you can fly on just a whiff of power. I've seen a 28lb model flying around on just a .40 two-stroke. I wouldn't be tempted to use a large engine for this distance event.

You can launch from a moving vehicle ... saves the weight of the undercarriage.

You could go to petrol, but there will be a need for a larger airframe.

You could research the work of other competitors ... and people flying endurance records. I expect that the AMA and such-like have details of the models which were used; but I don't know how to access their records.


beepee 07-03-2012 01:17 AM

RE: 100KM cross country flight.
This comes from my experience participating in cross-country competitions in Texas. These were timed events, not races. They were usually 3-leg circuits of maybe 50-60km/leg. Thoughts and recommendations:

1) Obviously, you will have to plan your battery and fuel capacity. The good thing is that you can do some testing to validate your estimated requirements.
2) Run gas. It has the highest power density for weight carried. I flew big stuff with either a Quadra 42 on magneto, or US41 on CH ignition. I carried about 1.5 ltr of fuel and had plenty. We ran some pretty fast legs to keep up with the times.
3) A large stable aircraft will make the handling easier. Big is easier to see at the distances the bird will be from the truck. You can't always be in close. I flew with a 1/4 scale Cub, or similar sized Super Decathlon. They worked.
4) Make sure the seats for the pilot and co-pilot are firmly attached to the truck. You don't want to be jostled around during truck maneuvers. We placed a piece of plywood in the bed cut to fit, then tied down the chairs with HD tie-wraps.
5) I strongly recommend goggles in the back, though I never used them (should have). The air gets very brisk back there and can make your eyes water to the point of hampering your vision.
6) Carry small 2-way radios between truck cab and flyers. Nice to have a co-driver to help in this area. Very important for the flyers to advise if they need to slow down or speed up to regain control for some reason, or if the driver needs to let the flyers know that a turn or stop is coming up.
7) Last point, I promise - on our last event I installed a Futaba Co-Pilot (the optical flight stabilizer), because there was a short section in which the plane flew over a canopy of trees and the pilot was IFR for about 5 seconds. 5 seconds that felt like 2 hours! The CP helped with this and anytime there was a loss of sight connection. You must be cautious if you use one though. They are not designed for long straight flight legs. Because the sun is usually to one side or the other, the CP will tend to lean the aircraft away from the sun. If you resist this with aileron, over time the CP gets confused and counteracts the steady aileron input. There was some real excitement getting through that bit of education, I can tell you. To counteract the CP, you have to input rudder. This results in a small amount of sideslip during the flight but gives you full and centered aileron control throughout.

I wish I could come down and take part. Cross-country flying is the most fun I have ever had flying RC, BY FAR!

Good luck,


bogbeagle 07-03-2012 01:30 AM

RE: 100KM cross country flight.
Sounds like fun, beepee.

It's something I've never tried. Might give it a go.

Of course, we'll all be arrested, if we travel in the back of a pick-up truck. Have to give that problem a little thought.

I have a couple of those HAL auto-stabilisers, which work very well.

JohnBuckner 07-03-2012 04:13 AM

RE: 100KM cross country flight.
Fortunately here in the wilds of Arizona it is not illegal to ride in the back of a pickup truck, only to not wear a seatbelt. That was easy to fix with a drill and some holes in the bed along with some old belts.

Many folks plan installing chairs and facing forward or rearward but what I found far better is just to sit low in the bed facing rearward with back aginst the cab. Usually just sitting on a butt pad of sorts this offers a protected position from the wind and more importantly eliminates the need to use goggles.

Also facing the rear hemisphere rather than the front sphere offers a greater field of operation without the need to avoid visual blocking from the cab.


beepee 07-04-2012 12:30 AM

RE: 100KM cross country flight.
Interesting John, we found facing forward from the back of the bed to be the best. Each way has it's plusses and minuses. You get more wind protection facing rearward, I agree. We liked facing forward as it gave the pilot the most natural control reference for those long hauls. It also was much better when the truck had to stop or slow down. Facing rearward, the plane may pass overhead and go out of view. We never had a problem with visual blocking from the cab. We tried real hard not to fly that low!



JohnBuckner 07-04-2012 05:58 AM

RE: 100KM cross country flight.
Yes as you said and most folks tend to mount up chairs and things to face forward and that makes the wind in the face and the eye watering thing worse. Most who have tried backward facing and sitting low thing tend to prefer that as do I.

Two years ago I ran an entry level competitive cross country thing at our club with a big differance. It was not an endurance event at all and required no additional tankage and we even had several electric entrys.

It was a rather a rally event and the route was only just over two miles out and back. The purpose was to get folks who would not have in anyway attempted this before. For a first time event I considered it little local victory with about ten entrys and that even included buddy cord teams (instructor/students) in other words folks who had not even yet solo'd were able to participate.

The XC sprint or rally was simple to score and required each team to predict their elapsed time for the run and the differance between that and the actual timed run was how they were scored. Simple and easy to run. Its been about two years now and there is a lot of rumbling to do it agine this summer and I suspect there will be around twice the entrys.

Another form of XC event I used to participate in some years back was ran by LVRC up in Las Vegas and it also required no special tankage. It was quite successful for quite a few years and used to draw upwards of thirty entrys twice a year.

This competitive event typically was a total of about 25 miles with five manditory pit stops along the way that were unknown and selected by the 'Hare' a CD who drove off first and selected the first unknown stop on the 'fly' and the 'Hounds' followed (the flyers) This was a form of the old motorcycle hare and hound desert races. Each team received a poker card at the five stops including the end and the poker hand decided the winner.

The real winners were the survivors of all the unknown landings and takeoffs that were required and reached the end to receive all five cards.

Here is a short vidio of one of the new fellows during orienting sessions at flying from the truck before my XC sprint event:



franc 07-04-2012 10:51 AM

RE: 100KM cross country flight.
Hi Marcel,

From a fellow South African. I have never done the event but a few guys from my club have (PRF in Cape Town). They use from a 1/4 scale super cub to an LT40 trainer and everything in between. Weeks before the event they do endurance practice flying around the club for hours testing fuel economy.
Get yourself issue 11 of South African R/C Modeller, as it has an article of the event with lots of details and photos of planes and teams. Last time round a chap flew a foam Nine Eagles Sky Climber glider using 8200 mAh of 3 cell lipos, running out of power only 5km from the finish.

Good luck, I believe it is a lot of fun.

jester_s1 07-04-2012 11:46 AM

RE: 100KM cross country flight.
I would think a slippery sport plane with a minimum engine would be the way to go, possibly an Ugly Stick or one of the club .40 racers. A .60 size stick with a .50ish 4 stroke engine would need a long runway to takeoff from but could cruise at maybe 70 kph. The .52 in my Cub burns 8 ounces of fuel in about 20 minutes running full throttle nearly the whole flight, so if you allow some margin for safety you could expect 2 hours of total flight time which means about 48 ounces of fuel. If you go down to 15% oil (perfectly adequate in a properly broken in 4 stroke) you could get away with a bit less.

kenh3497 07-05-2012 12:17 PM

RE: 100KM cross country flight.
Soylent Green is.............................. Ya I know the answer:)

hint, Charlton Heston:D

sorry for the hijack, couldn't resist. This does sound like a fun event!!


franc 07-05-2012 12:19 PM

RE: 100KM cross country flight.
Cannot contribute much to the original question, but I meant to include for interest and inpsiration this link to the late Maynard Hill's achievement. Click on TAM links for more info, but essentially he crossed the Atlantic with a FAI legal aircraft, i.e. 6 ft wingspan, weighing 6 pound empty, 11 pounds with fuel, powered by a .61 OS FS.


bogbeagle 07-05-2012 12:55 PM

RE: 100KM cross country flight.
My mate has an Enya .40 diesel engine, four-stroke ... does that thing sip fuel. Phenomenal reliability, too, it just refuses to quit, whilst ever it is getting fuel.

Not necessary for this 100 km project, but could be worth investigating for a more ambitious journey.

I noticed that Maynard Hill's model was consuming 2 ounces per hour ... my 1.80 Saito consumes that in one minute.; my YS 1.20 consumes that in 40 seconds. Yes, I know, apples and oranges. Still, 2 ounces per hour is phenomenally frugal.

JohnBuckner 07-05-2012 08:38 PM

RE: 100KM cross country flight.


ORIGINAL: kenh3497

Soylent Green is.............................. Ya I know the answer:)

hint, Charlton Heston:D

sorry for the hijack, couldn't resist. This does sound like a fun event!!


Hey Ken no problem and yes I have always tended to name most of my airplanes with sometimes tongue in cheek names[8D]

Cross country is tremendous fun and if you live where it can be done and you have reasonable roads to use.

On my longest nonstop flight some years ago on Route 66 which was 75 miles 65 of which was in reservation jurisdiction and a simple call to the tribal council resulted in a nice reservation police escort and they even argued amongst themselves over who got to follow the pilot truck.

Cross country Has been for years one of my favorite things to do although its not often you get the opportunity and who knows when the FAA NPRM is finally released this may all come to a stop and be moot.


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