Got a bit sidetracked again. Been spending extra time tutoring students for AP exams, plus I had a race to train for (and recover from).
Been doing a few small bits on the cowling. Figuring out an attachment method and getting the shaping done.
Just for motivation, I decided to assemble all the parts to see how this plane will look when finished.

Cowling attachment is all done, and I've got a pretty good idea of what the final shape will look like. I'm leaving most of the bottom open to allow for plenty of cooling air for the motor and esc.

You mentioned the Cobra 4130 390 kV motor you planned to use but, what battery voltage and capacity are involved?

I'm using a 540 kV Cobra in this plane. I have the 390 in a different model. Either way, I'm using a 6s (a pair of 3s packs in series) 5000 mAh pack.
For the 390, I'm using a 16/10 prop, and on the 540, I'm planning on either a 12/8 or 12/10.

I suspect that at 540 KV, you’re going to want a 13x8 or 13x10 to get into the 1600W+ snack bracket. But maybe you don’t want/need that kind of “piped 60” power.

David

I have been wondering about possibly using a 13" prop. My plan is still to start off with the 12", but I am going to be making the landing gear legs long enough to give me ground clearance is case I need the larger prop.
Just have to wait and see how the first flights go.

What would you recommend as the minimum pitch speed for a plane like this?

Originally Posted by trident58

I have been wondering about possibly using a 13" prop. My plan is still to start off with the 12", but I am going to be making the landing gear legs long enough to give me ground clearance is case I need the larger prop.
Just have to wait and see how the first flights go.

What would you recommend as the minimum pitch speed for a plane like this?

Jon,

I think this link will answer most questions about your motor:

http://www.innov8tivedesigns.com/ima...0-12_Specs.htm

I wouldn't look at it from a minimum pitch speed perspective. I would simply try to maximize the power/efficiency ratio on 6s for your motor. If you look at the table in the link above, in the Cobra/Scorpion legend system, you generally want to prop the motor in the yellow "bands". You will see that an APC 14x7 gives the best "ratio" for this motor putting it close to its 65A continuous rating. With that prop you'd be at 64A and about 1400W input. On a 13x8 prop the motor is slightly under loaded as it's now operating at 54A and 1200W. However, if you go to a 13x10, the motor overloads at 71A (you could probably still get away with it if careful with the left stick). This leaves you with a choice of going with either a 12x12 (57A/1250W) or, if you can find it, ideally a 13x9 which should put the motor in it's peak zone.

Conversely, you can think of these prop/power results as indicative of how good a choice the KV is for the application. If you'd gone down slightly in KV you could have propped up in pitch to a 13x10 or, IMO much better suited to classics, gone up in KV (600-650 KV) and you would have had more power available on a 13x8 prop. An example is the 650 KV Rimfire motor of similar dimensions which produces ~1800W on 6s and a 13x8.

For your motor there is also the option to go to 8s but most don't want to do that as it often requires twin 4s packs in series (due to many charger's 6s limitation). If you did, then your motor would be ripping with either an 11x8.5 or a 12x6 (~64A/1900W in both cases) with very different flight envelopes due to their pitch speeds of 102 and 72 (I'm assuming km/h but it's unclear from the table), respectively.

David

Thanks David.

Reason I was concerned about pitch speed was that I figured pattern planes should be flying fast, and doing their vertical maneuvers based on conservation of energy, not just raw power dragging them vertically. Don't get me wrong, I have no problem with a plane accelerating straight up, though.

I think I'm going to be using either the 12/10 or 13/8. Depends on what the straight-line speed with the 13/8 is versus the sustained verticals with the 12/10. Being a sport/scale flyer, I'm really not too concerned about that "piped 60" power you're referring to, although it might be fun to try!

Jon

Time for a few (potentially) stupid questions. Never installed retracts before, so this is all new to me.
How much clearance should I have on either side of the strut when it's retracted? I don't want to cut too much away, but I'm sure that, over time, the strut could get bent a bit and I want to make sure it will still retract properly. Also, how much clearance around the wheels?
Finally, I've seen a lot of guys line the inside of the cutouts with some 1/16" sheet. Is this necessary, or just for looks?

On a different note, I finally got around to weighing some of the built components. The fuselage, fin, and cowl all weigh 16.4 oz, and each wing panel is about 9 1/2 oz. Looks like I should be able to get it RTF at about 7 1/2 lbs.

Took a big step forward and glued the wing panels together. Next big challenge is going to be cutting out the belly pan and fitting the wing to the wing saddle, while keeping things square and maintaining the proper incidence.

Always hate to cut up a nicely shaped fuselage, but I went ahead and cut out the belly pan. Now time to shape the wing saddle and mate the wing to the fuse.

Wing fitted in place, and the proper incidence set. Need to add a bit of filler to the wing saddle, and then off to fitting the belly pan.

Starting to think that this model is jinxed. Seriously, right after I started it, my mother-in-law to a serious turn for the worse, and she passed away on New Year's day. And then last Friday, right as I got home from work, anticipating some serious building, I got a call from my stepmom. My dad had had a trip and fall accident. He broke his neck, and he had elected not to have stabilizing surgery. Dropped everything and flew up to Oregon to be with him. Thank God I got to see and talk to him before he passed, but he's still gone.

I'm still in a daze. My dad taught me how to build with those godawful Comet printwood kits. He was into rubber powered scale for a while, but gave it up when my brother and I got too big and physical. Many pleasant memories there. He never got into RC flying, but when he retired 3 years ago, he started thinking about it. I had promised him that this summer I was not going to teach summer school so I could spend it with him, returning the favor and showing him how to build a modern RC plane (no ARF crap here!) and teaching him to fly.

No I can't do that. I look at the Gitano, and can't get any enthusiasm to build. Looking at my other planes, I don't even feel like flying. For those of you who've been in this spot, how long until I snap out of this funk? Will I snap out of it?

>>No I can't do that. I look at the Gitano, and can't get any enthusiasm to build. Looking at my other planes, I don't even feel like flying. For those of you who've been in this spot, how long until I snap out of this funk? Will I snap out of it?<<

Sorry to hear about you losing your father. In regard to snapping out of the funk, that is you to you to determine. No one in the world can tell you the time it takes. Including all the smartest people trained in the area of human minds. However do know one thing that is for sure. TIME will heal everything. Give it enough time and you WILL feel better.

It is now up to you to decide what method you want to use to snap out of the funk. Some may use the excuse to feel sorry for themselves for the rest of their lives and wallow in pain. Some will pick up their boot straps and start to engage in a road to recovery. The choice is definitely yours. You may want to choose something in the middle of the road. Take time to grief and take time to share your pain with others in your family. Those are good things to get the emotions out of your system. Find something that you enjoy doing. Even if it is something totally mindless and non-engaging. The worst thing to do (unless you choose that for your life) is to do nothing. If the Gitano gives you bad vibes, put it away. Maybe you will pick it up again 10 years later. If you think you want to work on it to prove a point or yourself, go for it. Do hold a lot of expectations for yourself. Just doing things is good.

If flying airplanes will get your mind to another realm for a while as an escape, go get an ARF and fly it. If taking up a new sport will occupy your mind for a little while, go and engage in a new sport. Take up golf, there will be enough frustration that will last you a life time.

Good luck and remember to let as much time past as you can while engaging in your healing process. You WILL feel better eventually.

I am sorry for your loss.

Yes, grieve. You need to grieve. Let it all out, don't hold back.

Then, do what you want to do. Do what makes you feel good. Do NOT feel guilty about enjoying life now that your father has passed. I am sure that he would want you to enjoy life to the fullest.

You can't teach your dad how do fly RC but maybe there is someone else that you can "pay that forward" to. You could honor your dad by sharing with somebody else what he shared with you.

Hope this helps. God bless you and your father.

Doug