Official Freewing 80mm A-4E/F Skyhawk Thread

[seaviper]

Rcjetdude.... Congrats on the successful second flight! Considering an agressor scheme on a second Skyhawk myself.

Monty, just follow the update and you will be fine. That will get you to a flyable configuration. Then you can fine tune the battery placement at the field after your first flight.

Ryan...you have to "splain" that paint scheme on the MiG..lol.

<salute>

[RCjetdude]

RCjetdude: There still seems to be a lot of confusion regarding the correct point to measure the cg from. Can you confirm whether the last photo showing your cg measurement is your latest (185mm) or an earlier 195mm setting? Based on Xplaneguy/Ryan's posts (588 & 597 on page 30) it looks like your measurement in that photo to where the guns are installed is more like 200mm. Xplaneguy says that the cg should be measured from where the guns are installed. If the photo shows your latest setting then this may be 15mm to far aft?

Perhaps Ryan or Xplaneguy can clarify?

You are correct. I am referencing from the base of the gun mount and finding that it flies well at 185. If I kept that CG it would be 200 from where the gun plugs in or I could still go forward another 15mm according to Tony. I have noticed that the post where Alpha first presented the revised drawing has been changed to now be a range of 175 to 195 from the base of the gun. It's also interesting to point out that the photo in that post of someone balancing the plane shows it inverted with the gear down as well. So, I think as Seaviper said, the 195 from the gun base is a starting point and many are reporting fine results. For my plane, for whatever reason, my CG needs to be further forward. I could try it even further forward but I don't see a need to go any further back. I believe I am in the same basic range as Chris with mine. Note though that the battery placement had to be quite different on my plane than his. Maybe it is because I am balancing with the gear down and I have moved my receiver and board aft. I dunno...

[seaviper]

I just noticed my "jet Intake" decals were a bit high on the shoulder. So, after some careful persuading, I got them off. Then I replaced them with the ones from the kit. Those water slide decals in the kit are actually pretty nice. I like the water slide version better than the vinyl one I had because it goes over that bump on the intake better than the vinyl one did.

[RCjetdude]

Picky, picky....LOL

[dahawk]

RCJD,
Now I'm a little spooked trying the 5800 RT. I'm going to go for 185 even if I have to add some weight to the nose. I witnessed a buddy taking off at the prescribed 195 and it was not pretty.

Hawk

[RCjetdude]

I was ready to add nose weight myself with the RT 5800. So many are saying to just take this or that battery and place it at a certain place but I think you need to shoot for a particular CG and adjust to it. I would be curious if you shoot for 185 and balance it inverted and gear down where your battery would end up. I can't imagine as light as a receiver and the connector board are that moving mine back could make that much difference but stranger things have happened. Crxmanpat posted a pic of his battery placement and it was a lot further back than mine and did not report any tail heavy flight characteristics so it is a bit puzzling.

[crxmanpat]

Using the RT 5800 in mine, I had plenty of room to move it forward. I will be flying it with the RT 6250, which will help even more to get the CG forward a little.

[RCjetdude]

Using the RT 5800 in mine, I had plenty of room to move it forward. I will be flying it with the RT 6250, which will help even more to get the CG forward a little.

That's what I recall... your receiver must be made of lead.. LOL:Silly: You are replacing the fuse correct? I am curious if you will see the same battery placement/CG relationship or if it will be a little different...love the Bullpup decals by the way. Thanks again. :Cool:

[dahawk]

I have a 6250 too. Was wondering if that one would simply be too heavy overall. Clearly a little more flight time as exemplified in the A-10. I'll await Pat's report.

Hawk

[seaviper]

Here is my CG as flown in the video with tanks attached (accurate to within the width of my fingertips). Required ZERO trim. Even with tanks off.
Wheels up or down doesn't make that big of a difference really. The update will get you flyable. Adjust it after that.



Incidentally, I achieved this CG by using the Admiral 5000 (new one) and just shoving it all the way forward. My RX is in the front too. You need weight up front in the A-4. If you go and start moving things back then you have to move some weight fwd to counter it. The problem is you can only go so far fwd with the battery because of that bulkhead.
Here is mine

I set mine up based on the advice of Pilot Ryan. Following his direction made this the easiest maiden flight I have ever had. And he told me to set it up as per the update.

Hope this helps somebody. Now..it's a good day to fly. I feel like charging some LiPo's....<Salute>

[RCjetdude]

Here is my CG as flown in the video with tanks attached. Required ZERO trim. Even with tanks off.
Wheels up or down doesn't make that big of a difference really. The update will get you flyable. Adjust it after that.



Incidentally, I achieved this CG by using the Admiral 5000 (new one) and just shoving it all the way forward. My RX is in the front too. You need weight up front in the A-4. If you go and start moving things back then you have to move some weight fwd to counter it. The problem is you can only go so far fwd with the battery because of that bulkhead.
Here is mine

I set mine up based on the advice of Pilot Ryan. Following his direction made this the easiest maiden flight I have ever had.

Excellent. Thanks Patrick.

[The RC Geek]

That should make it more nose heavy. The battery is already full forward for 195.. Must be using heavier batteries than Admiral 5000.

I'm using a Roaring Top 35c 5800 pack.

[EDFjetpilot]

I have a 6250 too. Was wondering if that one would simply be too heavy overall. Clearly a little more flight time as exemplified in the A-10. I'll await Pat's report.

Hawk

Hawk,

I've flown with the RT 6250...no issue on weight


Sean

[xplaneguy]

RCjetdude: There still seems to be a lot of confusion regarding the correct point to measure the cg from. Can you confirm whether the last photo showing your cg measurement is your latest (185mm) or an earlier 195mm setting? Based on Xplaneguy/Ryan's posts (588 & 597 on page 30) it looks like your measurement in that photo to where the guns are installed is more like 200mm. Xplaneguy says that the cg should be measured from where the guns are installed. If the photo shows your latest setting then this may be 15mm to far aft?

Perhaps Ryan or Xplaneguy can clarify?

My CG is measured from where the gun is inserted, back 195mm (shown in post# 588). With tanks and full flaps deployed, I prefer 180-185mm back from the gun insert point, though I rarely flying this configuration due to frequent high winds here in California.

[RCjetdude]

I flew mine yesterday with an 878 gram Turnigy Heavy Duty and it did fine. The RT 6250 weighs 803 grams according to the specs at RCJetWorx.

[EDFjetpilot]

My CG is 175mm from where the plastic gun mount and wing meet, or 270mm from the trailing edge of the wing. I like my aircraft just a touch nose heavy.

I balanced inverted, gear down. No hump, no pylons, no tanks or missiles. Mine is a "clean" Blue Angel.

I'm using Roaring Top 5000/70Cs (770g) and 6260/35Cs (803g) about 35mm back from the forward foam edge of the battery tray. The 33g difference does not make a significant difference to the CG when in flight.

I've got 2mm of up evelator mixed in with flaps. I takeoff without flaps. Land with half flaps. I've been able to land power off with no wind, and about 10% throttle with wind.

Aileron low rate at 6mm. Elevator low rate at 13mm. I fly on low rates to meet my scale flying style.

FWIW,

Sean

[xplaneguy]

Yeah....my Turnigy Heavy Duty packs help to settle the jet during windy conditions, though I prefer the Admiral 5000 packs for ripping it on the deck. ;)

[crxmanpat]

My new fuse arrives tomorrow. Hopefully I will get it done by Friday as I have a day trip to LA on Saturday, then can fly it on Sunday before heading to St George next weekend.

[seaviper]

Worked on my hook and refueling probe today

[seaviper]

Since I am not using the hump for the aircraft I am modeling, I made mine into a removable camera mount.