Samu Mantyniemi's blog View Details
Posted by Samu Mantyniemi | Nov 01, 2013 @ 05:09 PM | 3,335 Views
Here is another ongoing project. I am converting my yellow EasyStar II to an FPV platform.

Eagle Tree guardian and the receiver are mounted on top of the wing and the 1.3 GHz video transmitter is on the tailboom.

I currently have a pan/tilt system for the camera but I have not mounted that yet. I am about to get a FatShark trinity head tracker for beta testing, and it has the roll axis as well, so I am thinking of adding another servo for the roll axis to the camera mount.

The camera mount will then need 3 channels, which means that I am out of channels with my 8 channel receiver (5 to the plane and 2 for the guardian). I am planning to use a small 4 channel receiver for the camera gimbal which means that I also need another transmitter module for the head tracker.
Posted by Samu Mantyniemi | Nov 01, 2013 @ 04:52 PM | 3,450 Views
After trying F5J with Riser and Cularis, I wanted something bigger that would also be more up to the task. I managed to get myself a used NAN Xplorer with a 3.8m wing and a glider fuse. I have ordered an e-fuse which should be delivered early next week.

I have not flown the glider yet, but once the weather and life permits and if I can get some experienced help, I am ready to try. I have the basic radio setup done, which obviously will need a lot of tuning once I get it in the air. My throws look quite large, so I will start with lots of expo on the sticks.

Xplorer 3.8 mixing and flight modes (2 min 19 sec)

Posted by Samu Mantyniemi | Nov 01, 2013 @ 04:36 PM | 3,277 Views
In one of the earlier posts I mentioned the test flights of the Fun Cub with floats on grass. Couple of weeks after that the Fun Cub got to see some real water, which was great fun. I had Initially some problems with not so good tracking of the floats, but after some twisting and bending it all started to work. The flying conditions were great with amazingly calm surface. I had a small keychain camera on board for most of the flights. Here are some selected moments:

On the Mirror (4 min 57 sec)

Posted by Samu Mantyniemi | Nov 01, 2013 @ 04:21 PM | 4,367 Views
In fact, I finished it already in August, but have not had time to update the blog.I ended up using the motor and prop that I saved from my Radian Pro which crashed last year. I used floor finish to glass the balsa fuselage, and made the battery hatch from depron.The end result looks nice from a distance. But I am most satisfied with the fact that I managed to build a model that actually flies!

I attended my first F5J contest in August, and took Riser and Cularis with me. I flew first three round with Riser, and used Cularis for the last three. I ended up the last one in the competition, but to my great surprise I managed to score 1000 points with Riser in one of the early rounds.

Now the Riser is hanging on the wall waiting for the calm and lazy summer afternoons. Here are a few pics about how it turned out.
Posted by Samu Mantyniemi | Jun 03, 2013 @ 01:55 AM | 4,813 Views
I completed the left wing last night. Still some final tightening of the covering to be done and the holes for nylon bolts must be drilled.

My first wing for 25 years, I am quite pleased with it.

Sig Riser 2m: finished wing and spoiler (0 min 18 sec)

Posted by Samu Mantyniemi | Jun 03, 2013 @ 01:41 AM | 3,851 Views
Very nice evening at the local park. I mostly flew Cularis for landing practice and also tried if Fun Cub would take-off from grass with floats. It didn't and had be to toss launched. Landing was challenging as well...
Posted by Samu Mantyniemi | May 26, 2013 @ 02:30 PM | 3,548 Views
Some progress with the wing. Final sanding needs to be done still, and the spoilers should be tested once more before covering the wing.

I managed to break some structures while building, so I already have some experience in repairing the damage...
Posted by Samu Mantyniemi | May 10, 2013 @ 12:04 PM | 3,924 Views
The left wing is taking its shape. The spoiler mechanism seems to work ok. Some more sanding for the LE and the tip.

The wing will be in two pieces with dovels at the front and vinyl bolts on the TE. The wing joiner will be made from brass tubes and a piece of piano wire like in the Riser 100.

I have not started the fuselage yet. Instead of power pod I was thinking of earlier, I am considering to make two swappable nose pieces. One electric and one for pure glider mode.

Sig Riser 2m spoiler prototyping (0 min 26 sec)


Sig Riser 2m: next step with the spoiler (0 min 26 sec)
...Continue Reading
Posted by Samu Mantyniemi | Apr 23, 2013 @ 06:37 AM | 4,267 Views
I had my SD card in the DHT-U module for months without reading and cleaning the log. There were more than 5 megabytes of data accumulated, with many of the instances just recording while I was programming the radio or testing different things.

I made a small R script which reads the log and writes a bunch of separate files, one for each time I had turned the radio on:

Code:
setwd("c:/models/flightlogs")
con<-file("data_log.csv")
open(con)
i<-1
stop<-FALSE
while(stop==FALSE){
t<-try(x<-read.table(con,nrow=1,sep=",",fill=TRUE))
if(class(t)=="try-error") stop=TRUE

if(is.na(charmatch("Frsky",x$V1))!=TRUE)
  {
  new_file<-paste("log",i,".txt",sep="")
  x<-read.table(con,nrow=1,sep=",",fill=TRUE)
  write.table(x,new_file,col.names=FALSE,quote=FALSE)
  i<-1+i
  }
else{
write.table(x,new_file,append=TRUE,col.names=FALSE,quote=FALSE)
}


}
close(con)

Posted by Samu Mantyniemi | Apr 22, 2013 @ 04:55 PM | 4,051 Views
The mail brought two GPS sensors today. The other one is going to go into Cularis, and the other I plugged into my EasyStar for the flying session at the local field.

It worked well. However, it took me some time to visualize the flight path from the log-file that DHT-U wrote on the SD card. I used GPS visualizer web site for the first trial. The key thing to realize was that DHT-U stores the coordinates as degrees, minutes and seconds, and those had to be converted to decimal degrees for the GPS visualizer.

The map below shows some of the flying from the latter part of my two-battery session.

I am sure that someone has already written a script that exports the DHT-U log to a map. Any pointers would be highly appreciated!
Posted by Samu Mantyniemi | Apr 21, 2013 @ 02:12 PM | 3,961 Views
I fixed the broken servo connectors, and decided to go for the maiden flight. The forecast was sunny with 2-3m/s, but once I got to the field the wind felt much stronger.

I checked the trim with two hand tosses. Some down trim for the elevator gave nice flat glide from the shoulder level. Then full throttle and a level toss, and the Cularis took off to steep and steady climb. I cut the throttle around 100m and tried to check the trim, which was a bit difficult due to thermal activity. I gained some altitude just by flying around and getting to know the plane. Then I decided to practice the landing pattern, which went very well. I could make the final turn well above the treeline and then just adjust the brakes and drop the plane to my feet. Great feeling indeed!

I spent three 2200mAh batteries while flying about three hours. There were big and strong thermals around, which even a beginner like me was able to exploit. Once I got so high that the orientation of the glider was hard to detect. I had to open full brakes and come down to more manageable altitude.

Now that the most dangerous phase is over, I will take Cularis back to workbench for some glassing and painting.
Posted by Samu Mantyniemi | Apr 19, 2013 @ 08:30 AM | 5,128 Views
Looking at the Sig Power Pod for a small engine, I started to think about a brushless version to be used when a hi-start is not available.

A plastic tube would contain the motor, ESC and the battery. Folding prop, maybe from EasyStar II, would be used as the pusher. The whole thing should then be located on top of the CG so that the CG would not move. Receiver would take power from its own battery as in pure glider mode, just the throttle signal would be fed to the ESC.

There must be many DIY experiments for this already, but for some reason my search was not very fruitful. Any links and thoughts would be highly respected!
Posted by Samu Mantyniemi | Apr 18, 2013 @ 02:31 PM | 4,345 Views
While trying first hand glides with the Cularis, I noticed that I am also a victim of the well known weak spot of the Cularis: the servo lead connectors of the right wing do not make a good contact. My Cularis was factory assembled (RR) so I had thought that everything should work fine with this individual.

First I tried removing the connectors that are in the fuselage. I drilled (well, half melted) the plastic away around the connectors and tried if the connection would be more robust now that the connectors are allowed to move if the wing shakes a little.

But that did not help. Then I noticed that the connectors of the right wing do not protrude as much out from the wing root as the connectors of the left wing. I tried to dig out the connectors, which were very well glued to theri place. I finally got them out using a sharp knife, but they did not survive intact from the operation. I tried to glue them back together and then glued them back to the wing but so that they protrude more than before. Will see if that was of any help or if the connectors are so full of CA that they do not work at all.

Another problem is that the right wing does not sit in its slot as tightly as the left wing. It looks as if the wing goes a bit too deeply into its hole, which then results in a small gap to the wing locking mechanism. I guess I have to add some padding to the wing root so that there is no room for any movement.
Posted by Samu Mantyniemi | Apr 18, 2013 @ 02:01 PM | 4,432 Views
The Riser kit arrived today. Last time I built something from balsa was 25 years ago. Blue Phoenix flew ok from hand launches, but I still managed to break the tail section many times and did not get into real flying after all.

Year ago I wanted to try flying again, and got myself Radian Pro. I broke it couple of times quite badly, but the repairs were very easy compared to the Blue Phoenix back then. Eventually Radian was destroyed when a wing joiner came loose midflight. Then I got myself FunCub and EasyStar II, which are great joy to fly. I am also about to maiden my new Cularis.

Now that I feel that I can handle the beginner foamies, I will try to patch my childhood trauma and build and also fly a balsa glider. Let's see how it goes. I built quite many free flight models before the Blue Phoenix, but after 25 years I feel that I have lost most of the practical skills.
Posted by Samu Mantyniemi | Apr 11, 2013 @ 03:18 PM | 4,580 Views
I received my receiver ready Cularis already last October, but have not had much time to finish it to flying condition. I recently had an excellent thermal soaring experience with my new EasyStar 2, and got the motivation to get the Cularis flying.

I finished all the channel mixes to achieve the surface throws suggested by the manual. (I am using Open9X). Balancing at the CG suggested by manual required 10 grams to be added close to the tail skid. With 2300mAh battery Cularis weighed 1596 grams.

There are still some important things to do before the first flight.
  • The elevator makes pinching contact with the vertical stab. Some foam needs to be removed from the elevator to ensure that it moves freely.
  • One of the prop blades sits quite tightly in the fork and may not fold properly. Some sanding of the fork and/or root of the blade seems necessary.
  • Check the orientation of the tapered collar that keeps the collet of the prop adapter in place. If the taper is to same direction than the taper of the collet, then the backplate of the spinner will touch the foam around the motor mount. If it is put on the "wrong" direction, then there is enough space between the backplate and the foam for free rotation of the prop and spinner. Maybe some washers are needed or then I just try to tighten the collet on another position.

Once those are fixed, it is time for the first flight. If it comes back in one piece, then it is time to start doing some light glassing and painting.
Posted by Samu Mantyniemi | Apr 10, 2013 @ 07:24 AM | 4,235 Views
I seem to get addicted to this hobby. Using a good deal of time on surfing around rcgroups, looking glider videos on youtube, thinking of buying more of them and nervously looking at weather forecasts for any positive signs. But it feels good!

And now I seem to start channeling any extra enthusiasm to blogging about it.