The Cyber Parachute Surfer.
Upgrading the Cyber-chute.
This page is pitched at the RC novice. Experienced RCers may already have the gear and hopefully the know-how.
This is an Australian site, prices mentioned are either Aussie or US depending on where I found stuff.
Currently one AU$ = US$0.81 , prices are just a guide so it doesn't matter too much.
As I stated on
page one – a well designed, well tuned paraplane could be
the perfect RC model for beginners – unfortunately the cyber
chute has it's failings.
problem is a sever roll to the right. The more power you have the
worse this gets. If you have inadequate power for climb the roll
problem is less sever.
Refitting any RC model is expensive, if it is the first one you're doing. The second one is much cheaper because you already have the transmitter, charger and parts you can borrow from earlier models. With only a motor and one servo the cyber-chute refit is likely to be cheaper than any most powered RC aircraft.
There are budget parts available, they are usually a bit heavier but if they work properly could be quite good value.
The cheapest (but
not cheap) and easiest improvement you can make is to put in a
decent battery. Even nickel-metal-hydride batteries (twice the
capacity of ni-cad) are pretty much obsolete and hard to find.
Genuine sky-surfers had an optional 1100 mAH NiMH pack but I doubt
you can buy one now.
The clone chutes are not particularly well made. Fortunately they fly better and last longer than you might expect. There are currently no alternatives that I know of. Genuine sky-surfer canopies are no longer available in most parts of the world. I think I got the last two to leave Japan. I have experimented with using kites but they won't fly well on a stock model. It is possible a kite can be made to work with a fully upgraded model - it is research in progress. Kites have more drag than the plastic sky-surfer chute so performance will be reduced. This is offset by the convenience of a cloth chute which can be folded and does not require spreaders – stay tuned for kite progress.
use a plastic chute compared by some to shopping bags. The rigging
is unusual. Most paraplane foils I've seen have four rows of lines
which terminate at two attachment points. Typically one group of
four lines is attached to every second rib.
The plastic chute
only has two rows. One set at the front and the other about one
third back from the trailing edge.
The lines terminate to four attachment points not two.
You can easily
convert a surfer to use a two line chute and you can also convert
a surfer chute to work on a two line model.
I should also
mention the canopy area has to be matched to the weight. A bigger
chute is not going to work nor is dramatically reducing the weight
of the stock model.
The full upgrade.
Other items you
may want to upgrade are – the radio receiver, the servo, the
ESC (speed controller) the motor and propeller. The bad news is
you pretty much have to do them all together. Everything in the
stock model is non-standard, probably the RF signal is also
non-standard – it is 27mhz which is illegal in many
Another hack which has been done is to add an extra control channel (and servo) to alter the AOA (angle of attack) of the chute in flight.
I usually use JR
gear for it's long range but it is expensive. Budget receivers
(RX) can be as low as $20Aus but quality and compatibility are
unknown to me. Remember control failure could result in the loss
of the model (upgraded and now worth hundreds of dollar), so it
might be worth a few extra dollars for a known brand. I've used
GWS ($32 for 6-channel) with no problems.
It is not essential to replace the motor but pretty much everyone does. Brushless motors are lighter, more efficient and some have enough torque for direct drive. On the other hand keeping the motor lets you use a cheaper ESC and lets you use any two cell LiPo you may have bought for it.
The most promising fix for the roll problem mentioned early is mount the motor so the thrust is off axis by about four degrees. This is hard to do if you keep the gearbox so direct drive brushless make a lot of sense.
Choosing the correct motor is difficult. You need to match the speed (RMP per volt) and have enough power. For direct drive you will need an “outrunner” type motor. AXI is one popular brand, there seem to be cheap motors about ($15) but I don't know how well they work.
My preferred motor is a CDROM style
motor. These don't actually come from CDROM drives any more but
use a similar design. I have taken to winding my own.
has kits starting at US$9 but a decent kit
with ball bearings and firewall mount is US$26.49. For a few extra
dollars you can get a double stator kit. You shouldn't need a
double but if you have room the bigger motor should run a bit
cooler and possibly more efficiently. I'm using a single for size
You can use the stock prop if you want but I didn't. There are three reasons why I changed.
The props I use aren't specially made to be pushers, you just mount them on the spinner to be a pusher. You might be able to find a push-on pusher prop that will fit but using a common prop has a lot going for it.
I'd suggest you match the stock size and pitch if you can unless you have a good reason to change it. Presumably the original designer/builder found this to be the best.
sky-surfer prop is part number HBZ78118 and is a 9*4 inch prop.
That is nine inch diameter and a travel of four inches per rev
(less in practice)
Your motor needs
an “electronic speed controller”. Brushed and
brushless motors generally use different controllers though there
are a few ESCs which can do both. Brushed ESCs are cheaper and
often simpler. I've used JETI brushed controllers and phoenix
brushless. Phoenix are good but once again not cheap.
Most ESCs will have some way to
configure them. The phoenix ESC can be programmed using the radio
TX or with a USB interface – I do the former.
The most obvious difference between controllers is there current rating. I'm putting a phoenix-10 (10 amp) into my surfer – this should be enough unless I want to add a lot a weight.
This stand for “battery eliminator circuit”. This might sound strange for something battery powered but it makes sense in that some older RC gear used a separate battery. Ie one for motor, one for radio and servos. All a BEC is is a five voltage regulator (sometimes six volt). All modern ESCs have a BEC built in. Some even have two – one for the motor controller on one for everything else – mainly to reduce RF interference.
In most electric RC aircraft you attach the battery to the ESC, when you plug the ESC into the radio BEC power (5V) is fed to the radio which then routes power to the servos which are plugged into it.
The ESC/BEC is a
crude linear regulator, they are inefficient – particularly
with higher battery voltages. A separate switched mode (efficient)
BEC can be used if required. A park-BEC is one I've used before.
If you are just going to run the steering servo you probably
The entire weight
of the gondola hangs off the servo. When I built my black
rainbow I agonized over torque and side load and bought
a fast, grunty, dual bearing hitech servo. It turns out the servo
doesn't have to be fancy. A basic futaba 3003 is one type which is
known to work.
didn't hold out much hope that there would be an easy fix for the
torque steering problem. Strangely only people with surfer clones
are reporting this problem so it appeared like it might be that
small paraplane flyers would have to live with it.
If you're interested in this stuff you should join the group.
Fred Garvey posted some notes to the group which I have copied here. Fred has informed me that he hit a snag in that his motors have been burning out rapidly. He puts this down to reversing the polarity to make them spin the other way. (The stock motors did strike me as being a bit small for the job.)
My Hack 1.
After that the motor didn't work properly any more.
lets see what we have here.
Note the prop shaft passing through the middle of the joiner which hold the fins. This means you can't put a direct drive motor in the logical position unless you modify the fins.
I chose to locate a small CDRom motor behind the joiner. Here I've ground away all the plastic where the motor will go. The motor is recycled from my black rainbow project. The joiner was later secured using a rawl plug up the middle and a plaster-board screw.
The cavity was filled with tissue and the motor tube repeatedly dipped in wax to build up a large blob which was then shaped using hot cloths iron, a cheese grater and any suitable carving tool that came to hand. When I had the desired shape, it was again hot dipped to completely cover the work area (and the floor) with a release layer to prevent epoxy touching the plastic.
The wax plug was made strong enough to prevent being crushed when placed under vacuum.
fibre cloth was wrapped around the plug and held in place with
sewing thread till in was vacuum
infused with epoxy resin. This was the quickest infusion I've
The broken cross-bar is being replaced by a 3mm carbon rod which locks the housing in position. When the bench testing is complete it will be bound in place with cotton and CA – strong but removable when the need arises.
By the way the strange lumps of putty are for flying a two string canopy – the servo extenders are moved back into these holes so they are closer to the COG (centre of gravity).
I've had a lot of trouble getting my single stator CDROM motor to work. I replaced the magnets and rewound it several times. It is now delta wound with 26 turns of 28 gauge wire per pole. It works but it is still getting very hot. The double stator motor I made for the rainbow (and now in the black thing) runs cool. I think I will be moving to double and triple stator motors in future.
Anyway it flew. It launch and climbed well
on the first attempt but the steering was terrible. My
cyber-chutes are both pretty sluggish.
The climb out was very steep and looked semi-stalled. It flew level on less than ½ throttle.
My setup was
The canopy was set for maximum AOA – this may have a bearing on the steering problem. The old cyber-chute canopy flew fine on the black rainbow gondola when converted to two string mode. It may be worth flying it on the cyber-chute in two string mode to see how it steers. It may also be worth adding some weight or using a stiffer servo arm.
I'm not sure if I will be doing any more on this.
The flight showed the offset motor does work – the model did
not torque roll as it used to.
If anyone is interested in working with carbon like I do – buying a cyber-chute and replacing parts with custom carbon one piece at a time would be a way to get into it without having to make everything in one go. If you replace the shroud with carbon you could probably increase the prop size to 10 inch for extra thrust.
If I did this again I think I'd totally replace the motor tube. It would mean changing the central fin attachment but would be easier overall.
May Day 2007.
Thanks to Len Martin for taking these photos.
I did some more test
flights at Nimbin where I have more space. All launches were
successful but the flights were fairly short because the motor is
still getting very hot – too hot for me to hold my finger on
the mounting screws after landing.
It appears the motor offset is about right when using full power but to much on a cruise setting.
I'm also now convinced the giggling/shimmying motion of the gondola in this and other models is a gyroscopic precession problem from the spinning prop. A lighter (carbon) prop would help here.
My Hack 2.