My 50 -cc gasser build thread

gauravag · December 13, 2009, 11:03:55 AM

Ok guys, i think the time has finally come for me to start building the Yak-54 , a 50CC gas airplane.
I bought this ARF from RCDhamaka in April this year, and took me the last 8 months to fund and collect the materials necessary for this giant airplane. Here is the what i have so far :

1. Yak-54 - 50CC ARF from RCD
2. Hitec 7955 Servos for all controls (5 in all). ( Chan, thank you for making me select these )
3. Futaba 3004 for the throttle.
4. Dual A123 2200mAh for the Rx power
5. A123 2200 mah for ignition
6. Heavy Duty Switches ( 3 )
7. Gold plated extentions from Rotor.co.in
8. DLE-55 with stock muffler/ignition.
9. Futaba 10CHP Radio on 2.4Ghz
10. Gas fuel tubing from Rotor.co.in
11. Jersey Modeller 1.25 Gallon Gas fuel can ( on order - from Subhobbies )
12. Lawnbnoy Ashless - breakin oil from Sunhobbies .

If all goes well, and as planned, i will be doing the maiden on Jan 1st 2010 .
I will need a lot of advise from others who are into gassers and giant scale airplanes.
Pictures, and build details to follow soon.
-Gaurav

anwar · December 13, 2009, 11:08:14 AM

Be sure to plan for some airflow on the 2.4Ghz receiver and keep it away from parts that get hot (it also helps to mount the receiver sideways).

Good luck with the maiden !

chanvivek · December 13, 2009, 02:33:06 PM

Hi Gaurav,

Very nice to see you start the build for this giant!! This is one hell of a flyer.. We flew the same model 2 days back in Chennai on a DA 50!! Flies superb and very true!

One small suggestion though.. Go in for a nice digital servo for the throttle as well.. Helps a lot for 3D when you require precision throttle control.. Though this might be debated, it is my personal opinion and I have used Hitec 5485 for the throttle!

All the rest all high end stuff and I am also building a CMPRO Extra 330L 50cc from Rotor. Engine is the DLE55. I would let you know how the engine works once we test fly it!!

- Chan

gauravag · December 16, 2009, 11:54:41 AM

Thanks Chan,
I will follow your advice and use the Hitec digital on the throttle. I have a few of 5485 in stock and would go for it.

One quick question, i cannot seem to find the spark plug for my DLE-55 . I think it did not come with it. Any idea from where i can get it ?
The recommended plug is NGK-CM6 .. Would it be available in India ?
I hope this does not hold up the project for long ..

Pictures to follow soon. I will be starting the hinge installation today.
-Gaurav

chanvivek · December 17, 2009, 11:43:21 AM

Hi Gaurav,

The DLE55 comes with a spark plug. Did you check the ignition box packet. It would be inside the spark plug cap! Please do check that once. I have no clue of where you can get an NGK plug here. I got a couple of spares from a friend of mine. I think you might have to order abroad. But check up on the forum once about the availability of Gasoline engine plugs! But I think there is a probability that you might have overlooked the plug in the engine box.

And good luck with your build.

- Chan

ankur · December 18, 2009, 11:00:07 PM

will be great to see a gaint scale plane locally

gauravag · December 19, 2009, 10:44:10 AM

Quote from: chanvivek on December 17, 2009, 11:43:21 AM
The DLE55 comes with a spark plug. Did you check the ignition box packet.

Thanks Chan. i did find the plug in the ignition packet ! Shows how much of dreaming i do than actual building !!

The ARF comes in a huge box, very well packed. Initially i was stuck by the size of the box, as i have been used to seeing 60-90 size ARFs so far.
On the outside of the box are a few pictures of Extra, Yak and Edge. Opening the box shows how neatly everything is packed. Tail surfaces look amazing ! i mean the stab/elevator can easily pass off like a 20 size wing !
The covering job has been very neatly done. There are some wrinkles but i am sure the heat gun can easily take care of them.
I am not sure how many times i will say this, but everything here looks huge ! The cowl is perfectly round, and is like a bucket. BIG !
There are carbon fibre tubes for joining the wing and stab halves. and the quality of the hardware looks good too.

The assembly starts with hinging the control surfaces. Good part is that the hinge slots are pre-drilled. Looks like there is very little work to be done. If i could get to work on this for full time, i am sure the setup can be completed in 2 days max.

The hinges are Robart style hinges, I have used them before on a Topflite Cessna, and using them here was easy. I put Vaseline on the jin, and then used epoxy to join the elevators to the stab. I do not have the deflection meter, but there is a lot of throw. Must be 45 degrees.
There is a slight hinge gap though. I will be sealing this with clear covering. Also, i MAY modify the trim a bit ( to aid visibility ) . The bottom of elevators have a black and aluminum stripe , but it does not extend on to the stab. I plan to do that.

One thing i noted was that the wood quality does not seem to be the best. The wings, though big seem to be a little on the heavier side.Since I have not yet owned a plane of this size, I cannot be very sure of this. I did weigh each wing half and it comes to around 625 grammes each. ( without servo/hardware)
The other thing that struck me was the very heavy landing gear ! . It it almost 350gms ! Wish, we had a carbon fibre gear here. Would have easily saved 200 gms.

Today i will be hinging the ailerons and rudder.
Then will come the installation of linkages, engine, cowl, canopy etc etc..

I will keep this thread updated as i progess.
-Gaurav

anwar · December 19, 2009, 11:37:41 AM

Pictures ?

gauravag · December 20, 2009, 09:34:03 PM

Will post pictures tomorrow.
Made some progress today.
-Installed the 5 servos
-Installed the main gear and tail wheel assembly

Since this is my first giant scale build, there are several things i am seeing for the first time, so may need some tips from others here on how to correctly set this up.
Firstly should i use the big aluminium horns supplied for the ailerons and elevator ? i know i will need to use the one for the rudder, but not sure i should bother to use these instead of the hitec horn for the aileron and elevator. If i use, then perhaps i would need to use the round horn and screw the aluminium horn to the round horn

Next, as to how to use the control linkage for the aileron, i will post a picture tomorrow on how i did, as i am not sure if its the right way.
more later...

gauravag · December 21, 2009, 12:59:47 PM

Ok, here are the pics of how i have mounted the aluminium horn and the ball link linkage for the aileron.
The round servo horn that came with the Hitec 7955 is installed on the servo, and on top of it the aluminium horn is placed and bolted to the round horn by 4 nos 4-40 screws with locknuts.
At the end of the aluminium horn the linkage is attached with another 4-40 bolt/nut.

I had to increase the hole in the aluminum horn considerable in order to make it fit the supplied hitec horn.

Am i doing this correctly ? I think the setup is good, but it comes out a little heavey with those 4 bolts and the aluminium horn.

Please share your views.
-Gaurav

anwar · December 21, 2009, 01:42:36 PM

As the picture is out of focus, can't quite see the 4 bolts/screws (and possible nuts) used; but looks sturdy overall.

If there are nuts involved, be sure to use a tiny amount of thread-lock where the metal bolt is in touch with the metal nut.

gauravag · December 21, 2009, 01:58:46 PM

I know the pics are bad. Here is an edited pic showing the bolts/nuts. I am not sure if this is the right way to do it, but thats the only way i could seem to guess.

At this point i would like to say that this ARF has surprised me. It is very well built and everything fits together as instructed. I have seem ARFs that are so frustrating to assemble, just because the screws/bolts do not fit as said in the manual.
I am glad that such high quality ARFs are available in India.

the only downside i have seen so far is that the manual really assumes that you know half the things. Like for me as a newbie for gassers i would have appreciated if they had explained how to assemble the horn and linkages. Yesterday i had a hard time figuring how the tail bracket would fit, but i guess thats the way how all Chinese kits are made.

gauravag · December 23, 2009, 06:12:38 PM

Here are some pics..

gauravag · December 23, 2009, 06:14:07 PM

Here is how i have attached the control linkage

gauravag · December 26, 2009, 10:38:19 AM

Ok, servos, control linkages all setup.

Now mounting the engine. The kit was provided with a DA-50 mounting template. Since DLE55 is slightly different, i downloaded the template from the website and used it to drill holes. This was very accurate and i seem to have engine up correctly. However i am not sure how to mount the throttle servo.
plus the engine has a choke lever. how do you use that ? Would be great if Chan could post a picture so i can see how you have it setup ..
Thanks !
Gaurav

chanvivek · December 27, 2009, 06:07:56 PM

Hi Gaurav,

I dont really think the mounting of a DLE55 is different from a DA50. I think both use the same mounting templates. I might be mistaken though.

Coming to the point regarding the throttle servo, the DA 50 throttle arm is in a different angle compared to the DLE55 making it easier to mount the throttle servo inside the fuselage directly. But the throttle arm on the DLE55 is in quite a difficult angle and once the engine is mounted inverted on the fuselage, it becomes a big pain to get the throttle servo to work flawlessly. I took about 5 hours to just get the throttle servo setup on the CMP Extra 50cc with the DLE55. One possible way is to also use the composite throttle arm extension that came with the engine. What I did on the Extra was that I removed the metal throttle arm and mounted only the composite arm in a convenient angle.

Regarding the choke, just use a pushrod as the choke lever. Put a small former between two standoffs and put the pushrod (with clevis) through the former and snap the clevis onto the choke arm. The other end of the pushrod should be accessible through the cowl from outside. So in order to choke the engine, we can push the rod and to release choke, we have to pull the rod.

Let me try and get some pics. My cowl is on so it would be difficult for you to see. And the DA 50 throttle / choke setup is slightly different from the DLE55

- Chan

gauravag · December 28, 2009, 08:42:52 AM

Thanks Can,
The mounting holes for DLE-55 are slightly different than the DA-50. Of course if you over-bore the holes then the there will not be a noticeable difference. The exact dimensions are 67mm x 80 mm for DLE-55 . The mounting template is provided here ; http://www.dlenginesaustralia.com/docs/dl50firewalltemplate.pdf

Now, i did mount the engine yesterday and also the throttle servo. I did use the composite throttle arm, but i mounted it on top of the regular arm and at the same angle. With the engine inverted the throttle servo was directly in line and the installation was not really a problem.

Choke pushrod would be something new for me, and i hope i do this correctly. Also where and how do you mount the ignition ? Should i wrap in foam, and use velcro to attach it to the side of the fuse ?
Also how have you setup the ignition kill switch ? have you mounted this inside the fuse and used a servo to actuate it ?

Thanks so much !
Gaurav

chanvivek · December 29, 2009, 09:55:15 PM

Hi Gaurav,

Good to hear that your throttle and the engine mounting was straight forward and relatively easy!! I would try and post some choke pushrod pics.. also try googling around to see the choke setup of other gassers as well.. You might in fact find a better solution..

The ignition mounting is also really simple.. You need not wrap it in foam.. Just make sure it is padded properly at the point where it sits in the airframe.. Just use some foam and tie wrap it whereever you feel it sits comfortably.. Just make sure it has ample foam packing in the bottom so that it is void of vibrations..

I generally program my throttle cut switch so that the carb barrel closes completely.. and hence cutting the engine..

- Chan

gauravag · February 21, 2010, 10:33:43 AM

Wanted to post an update here.
This project is currently on backburner. Reasons ? Still need ATC permission, and also been a little apprehensive on the transportation on such a huge model.
Should be back on this later this year though.
For now, HELIS !!!

gauravag · October 18, 2010, 09:02:58 AM

Ok Guys,
This project is back in action again.
I have got permission from ATC to fly this thing, and also had good success in learning Helis, so now its time to get behind this and complete it !
Will be posting a couple of questions shortly
Gaurav

gauravag · October 18, 2010, 01:26:11 PM

1. Gas fuel tubing, that i bought from Rotor, Chennai, seems to be too thin - Well this is my first gasser so i am not sure if it is normal for gas fuel lines to be thinner than their glow counterparts.
But the one i got from Rotor appears to be really thin.

2. I am planning to use dual power supply for the RX . I intend to use 2 Life 2100mah battery packs in parallel using 2 switches. Is this an OK setup to go with ?

3. What is the best way to install the engine kill switch. Manual or servo controlled ? If servo controlled, i gather that it will be done by using a servo to push/pull a linkage connected to a mechanical swiotch to on/off it ?

Thanks for all your help/suggestions !
Gaurav

gauravag · October 18, 2010, 03:27:58 PM

One more thing : SHould i use a servo to control the choke ? or just use a pushrod to actuate it ?

anwar · October 18, 2010, 03:50:15 PM

1. Not sure.. I have seen both glow and gas fuel tubes in various thicknesses, so I am not sure if this can be generalized.

2. If the packs are very similar, this is OK. Do not mix packs of various capacities (much difference in capacities), and preferably use packs from same brand.

3. If the ignition can be controlled remotely, that adds an element of safety. My brother made his own switch from a micro servo. You can get receiver controlled switches ("remote kill switch").

4. It seems to be matter of convenience, whether you want to make the choke servo controlled. Since it is all done on the ground, servo controlled ones are not a big deal, unless your carb is not accessible due to cowl issues. Even then you can rig up an extension rod to make it accessible.

gauravag · October 20, 2010, 10:42:47 PM

Quick question : I installed everything and found that the CG is a lot back than mentioned in the manual.
Now, to help solve this, i can place the 3 battery packs just behind the engine. This would place them pretty close with the ignition unit. Is this OK ? Or should the batteries be kept at a distance from the ignition ?

Harveer · October 21, 2010, 01:31:42 AM

Quote from: gauravag on October 20, 2010, 10:42:47 PM
Quick question : I installed everything and found that the CG is a lot back than mentioned in the manual.
Now, to help solve this, i can place the 3 battery packs just behind the engine. This would place them pretty close with the ignition unit. Is this OK ? Or should the batteries be kept at a distance from the ignition ?

Not a problem...its ok.