Archive | July 2012

Belly Camera

It’s been quiet lately while I am waiting for shipped equipment to arrive. In the mean time, I have some boring belly camera footage to share with everyone.

Some short snippets from Meerkat airfield. You can see the effect that the vibration has on the camera – I should really work on getting the motor better balanced.

Then there are some snippets from flying at Pretoria Radio Flyers. Having seen the first footage, I realized that with the current setup, I will only get good video with the motor off.

Its hard to get good down camera footage when flying “normally” and I’m sure it will be much easier to get “relevant” footage if the plane is flown in first person mode. Then it can be kept more stable during the glide and kept better aligned.

Next I’ll try to at least get long enough straight and level glides to make some image strips.

In my defense, this week-end was quite windy and it was hard to get those long stable glides!

I will upload the video later tonight and update this post with it.

First an image built using Microsoft’s Image Composition Editor.  This amazing program takes a video, and generate a stitched image from that, and it’s free too!  (Go here for more details).

Broken Camera – Follow Up

After some to and fro e-mails with the support at Security Camera 2000, my broken camera is on it’s way! It sounds like they will cover shipping both ways which is really great service.

They have already shipped the replacement camera to me, even before they had received the broken one – so they definitely cover the shipping back to me.

Their prices are reasonable, they ship for free internationally, and their guarantee covers international shipping too. You cannot ask for a better place to buy your cameras from, and I will gladly recommend them every time I get the chance to.

You can find their site here.

Broken Camera

When I first got the camera, I had it die on me right after unboxing. However, it came back to life shortly after that and gave me no issues until now.

Now it’s dead again and no matter what I try, I can’t get it to work again.

Now, usually having something die that was shipped from outside South-Africa, usually means that shipping makes it too expensive to return the item and that in effect, you lost the item.

After reading up on other people’s experience with Security Camera 2000, I contacted them, and to my surprise it seems as if they will cover shipping back to them and back to me, replacing the camera in the process.

I’m really impressed by this. If this is how these guys do business, I will gladly recommend them to everyone I know!

More Photos

Below is an assortment of photos dating from the start of my FPV exploits.

First SPAD

We built our first spad aircraft and flew it this week-end.  My daughter christened it “Shadow Fleet 1” (she’s an Ender’s Game nut, like me, and got her inspiration from there)

It flew beautifully and I’m sold on using this building tecnique in the future.

We did some gliding trials to check the basic aerodynamic soundness of the design (it’s this rookie’s first scratch designed and built plane!) and after a few adjustments, it glided nicely.

First powered flight didn’t go that well – it pitched up a bit, and on giving down elevator, headed straight for the ground.  I managed to pull it out of the dive for a hard landing / semi crash, breaking the prop.  Prop wash over the tail made it much more elevator sensitive than what I experienced during the gliding tests (probably a noob mistake by me!).

I flew it again, using dual rates on the elevator, and a bit of down trim.  This time, it flew very well, but still a bit pitch sensitive.  I then adjusted the servo linkages so that the was less throw on the elevators.  The third flight was absolutely perfect (see first video below).  Very stable and flew in boring circles around the airfield for around 15 minutes on 1/2 throttle (I wanted check endurance and low power characteristics).  Ended up consuming 1100 mAh in 15 minutes.

For the fourth flight, I loaded it up with a bigger battery, and added two more batteries to the “cargo hold”.  This pushed up the all up weight from around 800 grams to around 1.4kg.  To my surprise, it easily handled the extra weight, still maintaining level flight easily at half throttle!  I tested some stalls and it stalls so undramatically, that I ended up hanging on full up elevator, no power, and it just floated down.  I tried accelerated stalls, slow stalls, all kinds of stalls and could never get it to drop a wing – except maybe for the stall turns.  That setup equals the weight of around 2 x 2200 mAh batteries, which should equate to around exactly 1 hour’s flight time (as I could still use the same power levels as the endurance test I did).  The body has space for 3 x 2200 mAh batteries which I may try with a more powerful motor.

The last flight was with the FPV gear.  Unfortunately, I added quite a bit of “up” elevator trim on the last heavily loaded flight and with the plane now much lighter, ended up with the GC a bit aft from where it was (still good, but more to the back).

This caused the plane to pitch up again during launch and resulting in a hard landing and prop breakage again.  Sadly I was out of spare props at this stage and called it a day.

Third Flight – plane now nicely balanced

Will add more close up pics of the plane later.

Plastic Moulding

On a slightly different topic, but nevertheless relevant to FPV and RC in general.  A gear stripped in the Tiger tank used for the FPV gear testing.

Unfortunately, there is probably no chance of finding a replacement gearbox for this tank.

I have one of three choices:

1. Find a gearbox with similar characteristics, and replace the whole thing.  Which means I will have to replace both sides, and the tank will not run straight if the two sides are not geared exactly the same, with roughly the same resistances.

2. Find a replacement gear.

3. Make a replacement gear.

The latter two are probably the most viable options.  I’ll have to get the exact specs for the gear for option 2 (which I will do this afternoon).

Making my own, is a really interesting option.  It seems the most viable option is to make a silcon mould using a master (luckily, I can use the intact gearbox’s gear as a master).

Fortunately, I have a friend who have done this before, so I will be visiting him this afternoon to see how it works, and find out where one can find these products in South-Africa.

In the mean time, here’s some interesting sites on the topic:

1. Tutorial on silicone moulding.

2. Possible source for buying plastic gears.

3. Local supplier of moulding materials.

The ElectraSport

On request of a reader, I will post two photos of the crashed ElectraSport. Problem is, it’s nearly impossible to see the damage on a photo.

That little plane is nearly indestructible and have survived far worse crashes than the one this week-end. It wasn’t even a proper crash as it never really stalled. It just could not maintain level flight. So rather than pull on the sticks and possibly drop a wing, I let it run it’s course and cut power just before impact, saving the prop in the process.

If it wasn’t for that darned rock, it would have been an unplanned landing at most!

Anyway, here’s a photo of the damaged wing and snapped rudder, which broke due to rotational acceleration when the wing hit the rock.

The “crashed” plane with FPV gear on back:

20120702-233230.jpg

Crush damage on leading edge and crack in the wing:
20120702-233240.jpg

Snapped rudder:
20120702-233247.jpg