RCL Hawker Hunter, build log

[dennisp]

I make no excuses for this build as the Hawker Hunter is my generation (age...!) of aircraft, so when RCL produced the model it was a Must Have so to speak.

I would recommend that any purchaser or builder of this model does the following:

Read the build threads on RC Groups : URL’s

www.rcgroups.com/forums/showthread.php?t=1067968
www.rcgroups.com/forums/showthread.php?t=1074906
www.rcgroups.com/forums/showthread.php?t=1084476

And also go to the RC Lander web site and down load the addendum to the manual that is provided with the model. Read all the above carefully before you start and then you should not have too many difficulties.

The standing joke with the model group I fly with is, are you going to build it without any modifications...??, umm well this time I have tried to achieve this but there are some minor modifications that I have made which simple but important improvements, again some of these are mention in the RCG build threads.

The sequence of the build is almost (98%) to the instruction manual, so having made all the above statements time to glue this model together.

The Nose Landing Gear

The first task is to set up the Nose Landing Gear (NLG), for my model I decided to swap out the wire landing gear to the really nice RCL semi scale ones. In my case it was necessary to trim a little foam away to ensure the NLG goes up and down without any binding, this is paramount with mechanical retracts as any binding and up will go the current taken from the battery pack and a resultant shorter flight time.

You will also note from the pictures below the wheel well tub will require some trimming to ensure that there is no binding of this with the NLG.









Having sorted the swap out to the scale struts time to set things up, you can do this several ways either with your transmitter and a receiver or my preferred way is with a servo tester. The advantage of the later is less items on the bench and the capability to know what throws are going to be required to achieve the desired result. I shall be very honest up front and state that I am not a lover mechanical retracts but if you spend time setting them up correctly then they are fine.

The RCL scale retracts have a positive lock down and up so that there is no additional load on the servo when you return to mother earth with help of Mr. Gravity with bump (in my case a heavy thump..!). The pictures in the manual give some idea of the horns that are required, but I decided as an insurance I would check things out as I really wanted a positive lock down and hopefully a positive lock up as well, do note that lock down is more important than lock up for very obvious reasons.

A quick check of the supplied retracts and measurements of the retract push rod throws provided the following information :

MLG (Main Landing Gear)

30mm / 13mm which is the distance from the face of the retract to the servo push rod hole, the last 2mm each way are where the lock comes into play so we need a push rod movement of 17mm to go from lock to lock.

NLG

28mm / 11mm, again 17mm to go from lock to lock.

Using HS-65MG servo’s you can see in the following pictures where the EZ connector has to go and also the associated servo throws that are required.





My first concerns were that complex bent push rod wire that actuates the NLG, a little too springy for my liking but more on this later......

The Main Landing Gear (MLG)

The same process is repeated for the MLG, remove the old wire leg system and replace with the scale struts, first minor problem on removing the wire leg MLG I discovered the MLG mounting blocks were not glued to the wings. I need to be precise here in that there was glue on the blocks but it just did not bond to the foam....?, simple fix a dab of Epoxy and all was well. I then decided to check all the other joints including the NLG just make sure that the factory gluing was 100%.



At this stage of the build the wings are not joined, it is far easier to work on a single wing panel rather than a joined wing when setting the mechanical retracts up, the next pictures show the up / down settings.





You may be wondering why there is electricians tape on the servo, just another old habit of mine to wrap any glued servo in electricians tape and glue the tape to the foam, makes it easy to get the servo out later should this be required.

With this task completed time to move along to the fuselage.....

[dennisp]

The Fuselage

The design is a top / bottom split keel layout and all the initial work is carried out on the top keel first, following the instructions and also the addendum to the instructions the next step is to install the elevator and rudder push rods. I hope that you read the RCG threads that I posted at the start of this log as yes I can confirm that using the supplied push rod sleeves the friction of the wire in the sleeve is so great that you will never get good elevator and rudder control. I just happened to have some Sullivan push rods in the stores, so first modification replace the supplied sleeves with the red Sullivan outer sleeves.



Note the size of the rudder horn hole for the rudder push actuator rod, it is a lot bigger than the wire rod provided I was tempted to make a new thicker wire one but held back as I was trying to build this model with the bits in the box so to speak.

Now this is very important....... DO NOT GLUE anything at all yet....!!!, you will be in serious problems if you do there is a lot of trial fitting before you can glue anything so I will give the signal you GLUE NOW later.

The next picture shows the push rod routing to the front of the fuselage.



Time to TRIAL fit the fan..



Time to TRIAL fit the vertical stabiliser and horizontal stabiliser to the fuselage.




OK you can now remove the vertical and horizontal stabilisers from the fuselage and glue these. Now check the rudder push rod can pass through the vertical and horizontal stabilisers.



Now we glue the vertical and horizontal stabiliser assembly to the fuselage.



Time to move along to the rudder, I hope that you have not glued this....?, you will need to shorten the rudder control rod otherwise it will protrude into the exhaust duct. TRIAL fit the rudder and its control rod to the rudder push rod and control horn in the fuselage and shorten as necessary. Important step once you have completed this task is to grind or file a flat for the rudder push rod control horn to tighten on to, remember once this is joined up you have passed the point of no return once the model is assembled....!! (apologies for the poor picture quality).



If all is well so far then it is time to glue the rudder and its control rod to the vertical stabiliser, and check it moves smoothly using the push rod.



The next step is to prepare the fan for the associated mounting, I have used a Castle Creations 80 AMP ESC.



Now to the fun part, again if you read the RCG build thread the builder tried the method of placing a plate of plastic over the push rods in the exhaust area with not the required result. The best solution is to make a exhaust tube, consideration has to be given to that rudder control horn that sticks up in the exhaust area. So I opted for a exhaust tube that that extended just beyond the rudder control horn so as not to reduce the exhaust diameter at the back of the model.



You will still need to cut a slot for the rudder control horn in the exhaust tube.

To stop things moving around hot glue the outer sleeves for the push rods in the area under the exhaust tube, before going mad with the hot glue gun ensure that you can get the motor wires under the fan and between the pushrod tubes.

Now with everything checked out WE CAN glue the fan in with the exhaust tube attached using Capt. Harn’s tape method and the double sided foam tape supplied for the fan, and fit the rear bottom part of the fuselage.



Once the glue has cured time to move to the front of the fan, the ESC goes between the push rods and there are two small wood blocks on the side of the fuselage which I hot glued the push rods to.



Next step the front fuselage joining....

[dennisp]

The front fuselage

You need to fit the second battery plate now as it will not be possible once this assembly is glued to the fuselage, I was puzzled at first as to why the back battery tray support was higher than the front one. Once the front is glued on all became apparent, it has to be higher because of the complex MLG push rod and the idea being it maintains a constant position from the foam block in the top fuselage and the ply plate.



Once the glue has cured the fuselage should look like this..



The next step is putting it all together.....

[dennisp]

Putting it all together....

With the cables laying in the inlet duct they need to be restrained and held in place, I have used 5mm spiral cable wrap to make a loom for these wires, it does not show in the picture but you are going to need a short extension lead to reach the avionics area at the rear of the cockpit, As we ar going to need a BEC with this many servo’s I cut the red power lead on the extension cable rather than cutting the red lead on the ESC.



Now we can connect the elevator and rudder push rods to the servo’s, you may just be able to see the two tie wraps that retain the rudder push rod to the foam block at the back of the servo area. The elevator push rod does not seem to required this treatment as it is much stiffer being two rods joined by the “Y” link.



Now that we have sorted the fuselage end of things we can focus our attention back on the wings, fitting the servo’s and control surface horns requires no pictures as I am sure everyone can do this. Pay attention to the flaps, they will need a little piece of foam removed to avoid jamming. The design of the supplied control horns is quite nice no screws just two lugs position correctly push hard, remove and glue. In the case of the flaps, remove these from the wing (they are not glued anyway and then glue the horns in place as the lugs protrude through the flap and a little bit of glue (Epoxy) could just slip by and you have a permanent up flap situation...!

The servo covers require trimming but again not a difficult task, and once you have the servo’s in place I used double sided clear tape to retain in place. To ensure the cables do not fall out of the wing slots I have used UHU Print Stick glue, just fill the slots and lay the cables in place then remove the excess glue and they will stay in place but also allow easy removing of the servo if it is ever required.

Now the next big step, join the two wing halves, do not use 5 minute Epoxy use 30 minute or longer curing time Epoxy, as before perform a TRIAL check that the wings joins up nicely, give yourself plenty of room and if you need to jack things up to get things square make the bits of foam or cardboard now before applying the glue.

The strength of the wing is the carbon fibre rods, so ensure there is plenty of glue in the slots and the holes where the rods go into the wing. Your wing should now look like the MRT map with all those wires....!!



Before the next big step of fitting the wings all those wires need to be tidied up much like the fuselage ones.



I have used “Y” leads for the flaps and the MLG, but you can use a “Y” lead for the ailerons, just that I had run out of these leads.....!!, using the spiral cable wrap also acts a cable lock for the extension leads and also the “Y” leads.

So we are now ready for the mating process, again referring to the RCG build thread we have a problem Houston, the large wooden washers are too big to fit the recesses in the wing. Two choices here cut some foam away on the wing cover or do it the hard way and reduce the diameter of the wooden washers to fit the wing recesses, if you have a drill press it is a easy job bolt the washers together and file down with the washers rotating in the drill press.

The big moment... lay the wing on the fuselage and secure with the four screws wood and steel washers...



Now it starting to look like a Hawker Hunter...!!

The next step requires care.....!, when you fit the wing cover the screws supplied are too long and the back screws will pop through the side of the fuselage AIYO... NBG..!!



I have changed the back screws to 15mm length and the fronts to 25mm length.

We have almost completed the major assembly of the model and it does look very nice, well I think so.



Time to fit the receiver and the BEC which even with the 14 channel FASST receiver goes into the avionics bay a treat.



The next step is Gauntlet # 1 systems check out, I picked this term Gauntlet up from Boeing it seems to be the new BUZZ word, milestones and stage gates are in the past, OK I know that I am old...!!

The next step will be the Gauntlet # 1 testing just to move with the times ha-ha, and resolution of some issues that popped up during the testing, so stay tuned for the testing and resolutions to the issues coming soon on this channel on SKY Hobbies Forum (SHF)...

[cameraman]

Dear Dr,

It's all dennisps' fault. Before I started reading this forum, the 'need' to improve a models design was benign.

Now the urge is irresistable and the only original thing left is the box it arrived in.

Help!

Yours

Inverted Flymo Pilot (student)

[dennisp]

AIYO sir I am sorry if you are in re-design mode, but it can be very satisfying sorting out a mass produced model, but it can be frustrating and always time consuming as well...

[dennisp]

Gauntlet # 1, Systems tests

Power was applied to the model and the usual throws set up as per the values specified in the RCL manual, all seemed well so it was time for the servo exercise test to ensure that everything worked consistently and reliably.

After a few cycles the NLG was not a happy bunny and was either half way up, or down or anything where it should have been, it was a bit of a surprise as I had spent considerable time in the early part of the build as I had realised that the NLG needed some special attention in the set up. As anticipated the NLG push rod was flexing but now with the second battery tray plate in position there was also the friction when the rod bowed again this wooden plate. Some time was spent trying to resolve the situation and although it was possible to achieve a nice down or a nice up there was no way I could achieve and nice up and down.

I have always believed that mechanical retracts need straight or as near straight as possible actuator push rod, so sadly chaps it is modification time.....!!

After removing the 2nd battery support tray things were back to normal but that did not solve the need for the second tray, criteria I need a straight NLG actuator push rod. The solution is very easy, first remove the NLG and all the push rods, remove the NLG retract servo and the foam support for same and fit a wing mount type servo. The HS56 can be used as either a normal mounting or a wing mounting and I just happen to have a couple of these for another SSW project.

Here are some pictures of the set up as designed by RCL.









The HS-56 is mounted on three small ply plates and we have a straight line push rod for the NLG..... Bingo.



Before I make a new second battery tray, time for another Gauntlet # 1, servo exercise test, yes total success NLG steering OK and NLG up / down now 100%....

Oh dear I spot another problem the left MLG is not going up and down....... drat and double drat....!!

A quick check proved that the servo had passed away peacefully and gone to place in the sky where servo’s go, so a replacement was fitted and Yes we go through all the tests again, AIYO the right MLG looks a little odd too now..?, another quick check and it appears that the lock down mechanism on the retract is not working drat and treble drat...!.

So that is where I am at this point in time, the Capt. is providing a spare set of legs and once received I can begin all the tests again, before the fitting out of the office (cockpit) and applying the decals.

Sadly the first flight is delayed, umm just like that Dreamliner.....!!

So stay tuned guys for the next update on the Hunter.

[cameraman]

you forgot to mention expensive....

[dennisp]

MRO and Update time

The new MLG arrived and also a supply of “Y” leads so I could now fit a 7 channel receiver rather than the current 14 channel one which is installed, this also gave me the opportunity to re-route the elevator and rudder push rods to the correct location as this space was occupied by the 14 channel receiver.







This is a better push rod layout as they both nice and flat now, a small block of foam was added between the elevator and rudder servo just to provide a 4 point mounting for the servo’s.

The next step of MRO was the wing wiring, with less leads it was now possible to bundle the cables so that they would not get in the way of the retract servo’s and the associated push rods.



You will note in the picture two slots were made to locate the tails of the flap servo’s wire again for tidiness.

Wing back on the fuselage and the transmitter reprogrammed and lots of cycles completed to ensure that the retracts were reliable, and then the finishing touches build up the office a nice simple task you do need to shorten the height of the supplied pilot but this a no drama task, canopy on, nose cone on and finally the decals and we end up with a Hawker Hunter.

The drop tanks and wing stores are not fitted and pending successful initial flight these will be fitted later.



I have to say the finished model looks very smart and now it is wait time until the CTP returns from holiday to perform the maiden flight, initial date is the 2nd week of January, I will include some pictures of hopefully the Hunter scooting through the skies of Singapore then.