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Skymaster 1:7.5 F-4 Phantom

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Skymaster 1:7.5 F-4 Phantom

Old 08-03-2022, 10:44 AM
  #451  
SkyKnight
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Originally Posted by kevinthoele View Post
Alan

The 180 engines are plenty big for this twin

Yes, no doubt. I just have two on the shelf waiting for some action so I thought about putting them in there. I know of 2 others powered with 220RXIs. We'll see. I won't get back to that project until the fall.
Old 08-05-2022, 04:31 PM
  #452  
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Originally Posted by LA jetguy View Post
Congrats Jeff .. Looks real nice 👍

David
Thank you David.
Is your jet coming to you or are you having someone build for you?
i am curious how you are going to do operational canopies.
Upon closer inspection, I found several pressure dents on the bottom of my wing. John asked for pics, not sure how or if they can be fixed without filling and painting. I think it may have occurred during customs inspection.
Jeff
Old 08-05-2022, 04:51 PM
  #453  
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Originally Posted by F16Jeff View Post
Thank you David.
Is your jet coming to you or are you having someone build for you?
i am curious how you are going to do operational canopies.
Upon closer inspection, I found several pressure dents on the bottom of my wing. John asked for pics, not sure how or if they can be fixed without filling and painting. I think it may have occurred during customs inspection.
Jeff
Hi Jeff Ö. Mine will go directly to Jonathan Vogt ď. The lighter Side of RCĒ. We will do Air operational canopy..

David
Old 08-05-2022, 04:56 PM
  #454  
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Originally Posted by LA jetguy View Post
Hi Jeff Ö. Mine will go directly to Jonathan Vogt ď. The lighter Side of RCĒ. We will do Air operational canopy..

David
i thought you would be sending it to him. I will watch his build and see how he accomplishes the canopies.
Also I reached out to the person for the air actuated nose strut. I am going to order one when I am closer to begin the build.
Old 08-05-2022, 05:11 PM
  #455  
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Jonathan is working on my A10 now and soon on another F4 (1:7.5) so thatís next .. Mine will be closer to November
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Old 08-06-2022, 12:47 PM
  #456  
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Default Two F4e jets

Here are pics of my two F4e jets. Both Skymasters, one is 1/9.5 scale and the other is 1/7.75 scale. Going to finish the smaller one and then begin the larger one.


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Old 08-07-2022, 06:42 AM
  #457  
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Nice 👍
Old 08-23-2022, 12:01 PM
  #458  
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Default Couple short videos

I flew my F-4 this past Sunday, and was fortunate enough to have one of the members take a couple short videos. I havenít flown it since March 2022. Just clearing out the cobwebs. Planning to take it to Georgia Jets next month. Iím still working on the balance and trimming. Landing balance is about a half inch behind the front main rod. Planning to move further aft. Smoke oil makes it nose heavy for TO. I love the sound of a bifabricated pipe. Feel fortunate to have even short videos.






Old 08-23-2022, 01:48 PM
  #459  
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Originally Posted by RCFlyerDan View Post
I flew my F-4 this past Sunday, and was fortunate enough to have one of the members take a couple short videos. I havenít flown it since March 2022. Just clearing out the cobwebs. Planning to take it to Georgia Jets next month. Iím still working on the balance and trimming. Landing balance is about a half inch behind the front main rod. Planning to move further aft. Smoke oil makes it nose heavy for TO. I love the sound of a bifabricated pipe. Feel fortunate to have even short videos.

https://youtu.be/76f45QKXHC8

https://youtu.be/3m8iMvBF2_E

https://youtu.be/twtsC982ikA
On 1 7 3/4. Use 345 mm back from leading edge. I have two of them and itís perfect!!!
Old 08-23-2022, 04:42 PM
  #460  
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Originally Posted by kevinthoele View Post
On 1 7 3/4. Use 345 mm back from leading edge. I have two of them and itís perfect!!!
Thanks Kevin! It definitely needs to go aft that far for landing. I like a more neutral flight balanced jet. I just need to figure out what I can move aft without too much work. I wished that I would have plumbed the fuel system to burn the front center tank first. That way the balance moves aft as fuel is burned. I did this on my 1/6th F-16. Burns front tanks first.
Old 08-24-2022, 01:50 AM
  #461  
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Your F4 looks great,Dan!!! Very nice approach.

Mine is at 325mm and it works fine. Perhaps as Kevin says it could be moved a bit more aft, but I haven't dared that yet.
I have only 8 flights on mine, so.....



Last edited by kwik; 08-24-2022 at 01:52 AM.
Old 08-24-2022, 05:33 AM
  #462  
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Originally Posted by RCFlyerDan View Post
Thanks Kevin! It definitely needs to go aft that far for landing. I like a more neutral flight balanced jet. I just need to figure out what I can move aft without too much work. I wished that I would have plumbed the fuel system to burn the front center tank first. That way the balance moves aft as fuel is burned. I did this on my 1/6th F-16. Burns front tanks first.
once trimmed at this cg no trimming during flight. It feels very solid. I know it seems far back but I started at 310 and kept moving back till 345. Probably could
even go back touch more but I like the way it flys and lands so Iím done with cg moving.

good news about this plane is it flys fine heavy so if you wanted to add some weight to tail it would handle no problem to see if you like further back cg? Then you could figure what gear to move if you wanted weight gone.

anyway enjoy flying it!!!!
Old 08-24-2022, 11:31 AM
  #463  
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Originally Posted by kwik View Post
Your F4 looks great,Dan!!! Very nice approach.

Mine is at 325mm and it works fine. Perhaps as Kevin says it could be moved a bit more aft, but I haven't dared that yet.
I have only 8 flights on mine, so.....
Thanks for your compliment! Yours looks great too.
If you donít know the secret to a good approach to landing is trimming. Swept wing jets I trim level flight, gear flaps down, and jetís attitude 5į nose up. Usually around half throttle. Maintain the attitude through out the approach. Turning base, determine high or low. If high, reduce throttle stick back about 1/8 of what power setting for level flight. Maintaining attitude, the jet will start itís decent. If low, donít reduce power maybe until on final. If you listen, I carried power to the ground. For straight wing and sports jets, I trim half throttle, gear flaps down, and zero degrees nose up.
Just sharing my technique. Thank you again!

Last edited by RCFlyerDan; 08-25-2022 at 03:40 AM.
Old 08-26-2022, 10:53 AM
  #464  
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Dan,
Thanks for sharing your secret to a good landing. Question, where would you set throttle on a turn to base low, and final approach wind speed and direction east or ESE wind 2-3 mph.?
Old 08-26-2022, 10:58 AM
  #465  
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Oops I should have said cross wind 2-3mph.
Old 08-26-2022, 12:37 PM
  #466  
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Originally Posted by shepga View Post
Oops I should have said cross wind 2-3mph.
That is too difficult to determine with too many variables. And I think that you already know that concerning the question?

How low is low? Bank angle? Are you leading the turn with shallow bank? If you need to do a 90 degree bank angle, you over shot or are close to over shooting final, you need speed, and probably more power. If unstable? Go around. The jet is always safer in the air if the engine is running and you have fuel. How far out is downwind, then turning base? And turn to final? How much drag, tanks and armament, do you have hanging on the wings? I try to replicate full scale jets. If youíre a full scale jet pilot, think about the attitude and power setting flown with gear and flaps down, level flight. Usually during a non precision approach. And then, power reduction for step down and coming down final? You fly approximately 5-7 degrees nose up, there about, as a ball park figure that works well. You may be trimmed at 8 degrees nose up. Iím just visualizing and guesstimating as it appears to me. I say 5 degrees as a reference that the jet is in a nose high attitude and not zero degrees pitch up. To partially answer your question. If you are too low on the approach, and not stabilized, consider going around. Otherwise, Maintain level flight with your trimmed power setting, until you visualize intercepting a 3 degree glide slope lining up on final. Then reduce power to maintain a 3 degrees decent rate. Most airport ILS glide slopes are 3 to 3.5 degrees decent. But your question is truly too difficult to determine and based upon how consistent your approaches are flown. It also helps to visualize the ILS.

Old 08-26-2022, 03:51 PM
  #467  
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Thanks for the reply. I have a Feibao F4 Phanom which I haven't flown yet and I'm most concerned about the landing. I'll be sure to remember your advice.
Old 08-26-2022, 05:42 PM
  #468  
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Is this your first swept or delta wing jet? If you trim the jet for level flight with the gear down, full flaps, with a positive pitch attitude of approximately 5 degrees nose up, the jet will be on proper speed. Donít go higher than 10 degrees nose up unless you are applying power. Iím still feeling mine out. But feels like Iím coming down final at a quarter to a third throttle. With the positive attitude you do not want to pull the power early or get behind the power curve. If you feel like it is sagging, youíre pitching up, and applying power and still sinkingÖ.go around. Youíre behind the power curve, and will be difficult to save the approach for a good landing. If youíre pitching down, youíre high and probably fast.
If I may suggest for the maiden, that after you take off, level off and pull the power back to half. Do a couple laps for rough clean trim. Hopefully youíre flying flight modes, so that it makes trimming easier. Donít spend a lot of time on the clean trim. Donít take the jet through itís paces. Instead, trim for landing. At half throttle, extend the gear. If you want to reduce throttle to a quarter to slow before extending gear, then do. When you put the gear switch down, apply power back to half and extend approach flaps. Leave at half throttle throughout the trimming. Hopefully youíre using flight mode. Once youíre happy, again donít spend too much time with approach flaps. Then go ahead and extend full flaps. Adjust your trims accordingly for level flight. If your jet is powered on the high side, at half throttle you might be too fast. Reduce your throttle a couple clicks until you need to add a couple clicks of up trim to maintain approximately 5 degrees nose up attitude. Fly the race track for a couple laps. You want the jet trimmed hands off flying. If not, youíre not trimmed for landing. Then when comfortable, on base, reduce power an 1/8 of a stick. Maintain the attitude and youíll see the jet start to descend. Do not land on this approach unless things are perfect. Fluctuate your throttle from 1/4-1/3 down final to maintain a stable decent. At maybe a 100í or before, go around leaving gear and flaps down. Apply power, while pitching up, leave gear and flaps down. When you reach pattern altitude. Simply lower your pitch back to 5 degrees nose up, and pull power back to half or whatever it took to maintain level flight. The jet is now stabilized again. Take time to breathe, and do a couple more if needed. Otherwise, touch down with the approach that you feel comfortable with landing. I hope that I didnít go overboard with explanation. Too many go up to see what the jet will do, rather than properly trimming for landing.

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Old 08-26-2022, 05:47 PM
  #469  
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Default Couple still pictures from video.


I snapped a couple pictures out of the video. You can see that I am holding the positive attitude.

This is coming across the numbers and the attitude that you want to hold. About here I am going to idle.

Same attitude all the way down final.
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Old 08-27-2022, 01:08 AM
  #470  
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Hi all,
I am building this model and would appreciate your advise about pipe installation.
The model has a built in 3-3.4 deg. pitch up on the turbine mounts, so there is no way to align the SM pipe with the turbine without increasing the angle.
Only at about 6 deg. the outlet of the pipe becomes horizontal and looks like I'm going to cook my tail like others reported.. In order to point the pipe just a bit down and have the inlet aligned with the turbine, the turbine has to be mounted at about 7-8 deg which looks a lot.
I thought about using a different pipe like the one Grumania makes: https://www.grumania.com/xtcommerce/...ale::1042.html
Does anyone has any experience with this pipe? It is a straight pipe (pitch wise) like the Tams that everyone reports very good results with, but as far as I understand the difference is that the Tams has an inward angle at the end to align it parallel with the longitudinal axis of the model.
Since the Grumania one blows down and outwards (symmetrically though) would you worry about high speed flow near the outer side of the elevator? (other than heat)
What would you suggest? I prefer not to start with inverting the SM pipe for the first flight.
BTW, I will be using a merlin 210 for power.
Old 08-27-2022, 04:20 AM
  #471  
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I would contact hiep pipes and get a straight pipe from him. He used to make the tamjets ones.

https://m.facebook.com/100023972793042/

the SKYMASTER one will cook your tail and generate throttle to pitch coupling which is a pain in the *****
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ron ron (08-29-2022)
Old 08-28-2022, 07:54 AM
  #472  
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Hi Ron,

In my F-4, I have a Jetcentral Mammoth inside a bypass using the stock rail mounting angle and the stock tail pipe. The pipe is not inverted, but the pipe outlet is located at the lower portion of the aircraft turkey feather nozzle. You have to trim the mounting structure to let the pipe drop down. I have no trim changes with speed and there is no heat damage to the stab or aircraft underside with the outlet at the lowest point in the nozzle. Note that I do apply aluminum tape to the underside of the stab and aircraft rear underside in case of excess heat/flames that might happen during start, etc. Also make sure there is a vent hole (1/8 or 5/32 inch hole) in the stab roots to let out hot air or it will damage itself when the exhaust heats the stab up! In terms of performance the jet will do well over 200 mph.

Cheers
Old 08-29-2022, 02:04 AM
  #473  
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Here is my jetpipe. I don't know what type it is, but I suspect original Skymaster? It has a 5 deg bend, and is now arranged to point downwards at the end, as described below. This means the exhaust now exits 5 deg downwards, instead of in parallell, as earlier.









Last edited by kwik; 08-29-2022 at 09:55 AM.
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Old 08-29-2022, 09:56 AM
  #474  
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A friend did this video of the weekends flying;

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Old 08-29-2022, 11:57 AM
  #475  
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Originally Posted by JDjetjock View Post
Hi Ron,

In my F-4, I have a Jetcentral Mammoth inside a bypass using the stock rail mounting angle and the stock tail pipe. The pipe is not inverted, but the pipe outlet is located at the lower portion of the aircraft turkey feather nozzle. You have to trim the mounting structure to let the pipe drop down. I have no trim changes with speed and there is no heat damage to the stab or aircraft underside with the outlet at the lowest point in the nozzle. Note that I do apply aluminum tape to the underside of the stab and aircraft rear underside in case of excess heat/flames that might happen during start, etc. Also make sure there is a vent hole (1/8 or 5/32 inch hole) in the stab roots to let out hot air or it will damage itself when the exhaust heats the stab up! In terms of performance the jet will do well over 200 mph.

Cheers
Hi,
This is exactly what I was hopping to do but there is no way (on my model) to align the turbine with the inlet without almost doubling the turbine angle. Without doing so, I'll have my turbine blowing directly on the upper side if the inlet (straight portion of the pipe before the splitting point) which I am afraid is a failure waiting to happen.
How did you aligned yours?
Thanks!

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