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RE: Skymaster F-4E phantom
ORIGINAL: EASYTIGER Maybe you used a METRIC sliderule? They won't work on a plane built here in the USA. I used a sliderule made in china....they break apart at numbers exceeding 10Gs *g* OK, back to topic :-) |
RE: Skymaster F-4E phantom
Good catch, Bobber! The corrected figure by Gordon Mc might give a false impression of lower G load. Trying a more realistic 200mph at 300ft turn radius which gives almost 9G[&o], which is very attainable for many jet models. Also want to clarify that I'm not advocating extensive calculations or testing of kits before going to market. For a $7000 to 10k+ kits, some delligence seem not too much to ask for, besides the usual test flights. I recall seeing a picture of Peter Michel's large airliner model having to pass a static sandbag loading test. Haven't check the AMA experimental class requirements, but I'm guessing it might be there.
BTW, my simple 10-G static test was not intended as a destructive test; but just a pre maiden flight check for the simple calcs of the extensive spar carry-through redesign in converting the JHH F-4 to EDF. I can assure all it was an inexpensive & not at all time consuming excercise; although it sure gave me the warm & fuzzies. Just my 2-cents:D Phil |
RE: Skymaster F-4E phantom
Yo ET,
I gotta dissagree with you on one thing. I don't just buy 'cause its a good deal, usually...!:D Two factors come into play 1. I gotta like the plane 2. Its gotta be an arf If those two criteria are satisfied, then I go to the "how is it built?" then "how much does it cost?" questions. Like you know, I bought a non tested airfram from St. Nguyen because I liked the plane and we agreed on a price! He couldn't get me to touch his Rafale or his hawk 'cause I simply don't like them!! I'm waiting for the St. Nguyen blessed F-18 inspired Cadillac Escalade, "Presta" edition, with the matching trailer "Super Hornet edition" all sittin' on 22" spinners!! As soon as I get a good deal on that, I'll buy!!!:D But Adil, this F-4 tickles me pink!!:D (or purple with a blue stripe with a woody wood pecker...can I say that on RCU???:)) I can't wait till I can buy it painted! Raf |
RE: Skymaster F-4E phantom
ORIGINAL: ravill Yo ET, I gotta dissagree with you on one thing. I don't just buy 'cause its a good deal, usually...!:D Two factors come into play 1. I gotta like the plane 2. Its gotta be an arf If those two criteria are satisfied, then I go to the "how is it built?" then "how much does it cost?" questions. Like you know, I bought a non tested airfram from St. Nguyen because I liked the plane and we agreed on a price! He couldn't get me to touch his Rafale or his hawk 'cause I simply don't like them!! I'm waiting for the St. Nguyen blessed F-18 inspired Cadillac Escalade, "Presta" edition, with the matching trailer "Super Hornet edition" all sittin' on 22" spinners!! As soon as I get a good deal on that, I'll buy!!!:D But Adil, this F-4 tickles me pink!!:D (or purple with a blue stripe with a woody wood pecker...can I say that on RCU???:)) I can't wait till I can buy it painted! Raf |
RE: Skymaster F-4E phantom
ORIGINAL: PhilLin Good catch, Bobber! The corrected figure by Gordon Mc might give a false impression of lower G load. Trying a more realistic 200mph at 300ft turn radius which gives almost 9G[&o], which is very attainable for many jet models. Also want to clarify that I'm not advocating extensive calculations or testing of kits before going to market. For a $7000 to 10k+ kits, some delligence seem not too much to ask for, besides the usual test flights. I recall seeing a picture of Peter Michel's large airliner model having to pass a static sandbag loading test. Haven't check the AMA experimental class requirements, but I'm guessing it might be there. BTW, my simple 10-G static test was not intended as a destructive test; but just a pre maiden flight check for the simple calcs of the extensive spar carry-through redesign in converting the JHH F-4 to EDF. I can assure all it was an inexpensive & not at all time consuming excercise; although it sure gave me the warm & fuzzies. Just my 2-cents:D Phil |
RE: Skymaster F-4E phantom
Trying a more realistic 200mph at 300ft turn radius which gives almost 9G[&o], which is very attainable for many jet models. Call me crazy but I have not seen many 40+lb (wet) scale RC planes going 200 mph and turning in a 300 foot radius. How many of you guys have seen that ?? I've personally done that and seen others do that all day long (even tighter radius) with lighter sport planes but .... Maybe its just me but I think sometimes we get too ahead of our models :D:D Adil |
RE: Skymaster F-4E phantom
Hi Adil:
I am not sure but I would not confess anything that would cause stress failure and endanger life, especially were it can be seen by all. Just an opinion,,,, Dave ;) ORIGINAL: Adil Nasim Trying a more realistic 200mph at 300ft turn radius which gives almost 9G[&o], which is very attainable for many jet models. Call me crazy but I have not seen many 40+lb (wet) scale RC planes going 200 mph and turning in a 300 foot radius. How many of you guys have seen that ?? I've personally done that and seen others do that all day long (even tighter radius) with lighter sport planes but .... Maybe its just me but I think sometimes we get too ahead of our models :D:D Adil |
RE: Skymaster F-4E phantom
ORIGINAL: Adil Nasim Call me crazy but I have not seen many 40+lb (wet) scale RC planes going 200 mph and turning in a 300 foot radius. How many of you guys have seen that ?? |
RE: Skymaster F-4E phantom
Must be my estimates not in same ball park as others. In which case it may be time for some Eagle Tree on board system measurements:D. Should not be surprised if a few folks put their jet models over 10-G with their more energetic manuevers. A300ft radius loop with the bottom at 50ft above the deck only takes you up to 650ft. I know its not legal to break thru 400ft, so don't do it on my account;)
Cheers, Phil |
RE: Skymaster F-4E phantom
Hi Gordon:
I ask this because I do not know,,,, is there a G meter that can be small enough and lite enough that can be put in our planes? Dave ORIGINAL: Gordon Mc ORIGINAL: Adil Nasim Call me crazy but I have not seen many 40+lb (wet) scale RC planes going 200 mph and turning in a 300 foot radius. How many of you guys have seen that ?? |
RE: Skymaster F-4E phantom
yes there is. Eagletree has a G meter that works on 2 axis and is the size of a micro servo.
Voy ORIGINAL: WhoDaMan Hi Gordon: I ask this because I do not know,,,, is there a G meter that can be small enough and lite enough that can be put in our planes? Dave ORIGINAL: Gordon Mc ORIGINAL: Adil Nasim Call me crazy but I have not seen many 40+lb (wet) scale RC planes going 200 mph and turning in a 300 foot radius. How many of you guys have seen that ?? |
RE: Skymaster F-4E phantom
Voy have you tried one?
Dave ORIGINAL: wojtek yes there is. Eagletree has a G meter that works on 2 axis and is the size of a micro servo. Voy ORIGINAL: WhoDaMan Hi Gordon: I ask this because I do not know,,,, is there a G meter that can be small enough and lite enough that can be put in our planes? Dave ORIGINAL: Gordon Mc ORIGINAL: Adil Nasim Call me crazy but I have not seen many 40+lb (wet) scale RC planes going 200 mph and turning in a 300 foot radius. How many of you guys have seen that ?? |
RE: Skymaster F-4E phantom
yes i have .. Last i used it was on my KingCat. It wasinteresting to have m spotter calling out real time speed and G loading values to me while i flew. Neat gadget !
Voy |
RE: Skymaster F-4E phantom
I've got a great idea, Adil....
If you just limit stab travel to 1/16" up and 1/16" down, you will never overstress the airplane with excessive G's.[&:] Woj...I know there is really know way of telling, but how accurate do you think the G-sensing thing on the Eagletree is? I know you measured 50g's or something like that in some manueuvers, do you think that's real, or maybe a figure that was beyond the accuracy and sensing ability of the unit? I have no idea, I was just wondering. What does Eagletree say are the limits? |
RE: Skymaster F-4E phantom
ORIGINAL: EASYTIGER I've got a great idea, Adil.... If you just limit stab travel to 1/16" up and 1/16" down, you will never overstress the airplane with excessive G's.[&:] Woj...I know there is really know way of telling, but how accurate do you think the G-sensing thing on the Eagletree is? I know you measured 50g's or something like that in some manueuvers, do you think that's real, or maybe a figure that was beyond the accuracy and sensing ability of the unit? I have no idea, I was just wondering. What does Eagletree say are the limits? my 50 G estimate on a BobCat wing failure was not derived from the eaglet tree unit. For that one i took a VERY conservative estimate of the speed the plane was traveling at, and also a very conservative estimate of the turn radius based on a common consensus of those who saw this ... we ran the math from there ... as for the eagletree unit, i have no reason to think it is not accurate .. on the king cat i had it up to i believe like 16 or 17 Gs in a tight turn. I think a good way to see how accurate it is ( or if its even close) would be to take video of a plane doing a nice symmetrical loop at a set speed (can be done with a speed limiter on the ECU) .. do the math on the speed / vs loop diameter and see if the reading off of the eagletree is in the ballpark .... I would not worry about the whole G thing on the planes you fly however …. Foam makes for very light wing loadings ;) Voy |
RE: Skymaster F-4E phantom
OUCH!!!!!!!!!!!!!!!!:D
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RE: Skymaster F-4E phantom
ORIGINAL: G.KERR JR. OUCH!!!!!!!!!!!!!!!!:D It would be a GREAT Father/Daughter project for you and him! :) |
RE: Skymaster F-4E phantom
1 Attachment(s)
A couple of more hours last night and got the wings and tail group finsihed.
Here are some shots of the elevator. VERY tight linkage, I can't even move it a hair in any direction. Adil |
RE: Skymaster F-4E phantom
Nice piece of engineering.
I thought you were getting a reversed servo for one side...if so, why the matchbox? |
RE: Skymaster F-4E phantom
Still waiting on the reversed one [:o][:o] Horizon is a little late.:D:D
Could not wait any longer so i decided to use the matchbox. I'm actually glad as after going through 8 new 8611a I just got, i could not match two with the same throw and spline neutral point. Matchbox saved the day. Adil |
RE: Skymaster F-4E phantom
nice install, but i would not personally feel safe with the match box on the 2 servos for the elevator .. If i was to use a matchbox, i would put it behind a power box or some sort of power bus .. im asuming those are 8611 servos , and I know they are impossible to get matched up, so you do need a match box ... or how about a pair of Hitec 5955 servos ? didn't you hve a bunch of those ? anyway, thats just me and my paranoia ..
looking good man .. Voy |
RE: Skymaster F-4E phantom
I see. You could also(maybe) flip one servo around and put it behind the other to get the right throw, with a longer linkage(geometry stays the same)...but that does not help if the two servos do not center the same.
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RE: Skymaster F-4E phantom
ORIGINAL: wojtek nice install, but i would not personally feel safe with the match box on the 2 servos for the elevator .. If i was to use a matchbox, i would put it behind a power box or some sort of power bus .. im asuming those are 8611 servos , and I know they are impossible to get matched up, so you do need a match box ... or how about a pair of Hitec 5955 servos ? didn't you hve a bunch of those ? anyway, thats just me and my paranoia .. looking good man .. Voy Dude, You read my mind.. I used the Hitecs on my flaps and all it took was 2 seconds on the programmer to reverse one. They perfectly matched and work flawlessly. I continuously ran the servos (8611A's) for 10 minutes with a load on the elevator and they did not heat up or anything. I tried different servo locations with one longer rod but just was not getting the loads right. I did not close out the back for this reason. I don't feel comfortable with the match box on elevators. I'll try out the reversed servo when it arrives or it is time for the Hitecs. Adil |
RE: Skymaster F-4E phantom
heres the problem i have found with matching 8611 servos ... if you get them centered to eachother, the end points will slightly be off .. if you adjust this with a match box, and now you have the center and enpoints to match, i have found that the travel "curves" might still varry through the transitions between center and the end poinits ... and on top of that i have also found that speeds might slightly vary also between the 2 servos ... great servo for a single surface, but not for ganging up ..
Voy |
RE: Skymaster F-4E phantom
You could also mechanically gang the two stab linkages together(they aren't tailerons) and use one monster servo, or the two you have. They won't be fighting each other...much, would they? But the two surfaces will travel identically, and that's what matters.
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