The early B707-120/138 aren't easy to fly well .... at first .... but .... if one learns to master these aircraft versions .... then one shouldn't experience any difficulty, whatsoever, flying any of the later B707 SERIES .... all of which are much easier in comparison.
Remember .... B707-120/138 are old turbojet powered aircraft with much less agile performances than their fanjet/turbofan powered and aerodynamically improved B707-120B/13B and later family versions .... each of which perform quite differently.
"IF" flying the B707-120/138 around the circuit and with just 13% total fuel remaining .... then I'd say you're running your fuel reserves down to pretty dangerous levels and risking a flame-out. I'd recommend flying circuits with no less than around 20-25% total fuel remaining .... which is roughly what one should be planning to arrive with at their destination airport .... and which should guarantee sufficient virtual fuel for at least 3 circuits/approaches to landing.
The heavier the B707-120 is .... then the more sluggish its performance is going to be and which is quite in line with the actual aircraft too. Performance will improve as fuel weight is burned off.
That ROC is about right/what I would expect if heavy .... but .... I recommend using climb rate to keep the speed fairly constant throughout the the climb .... but .... which will also result in progressively lower climb rates later during the climb to target cruising altitude.
I'll share my own procedure with you ....
PLEASE NOTE .... none of what what I'm about to recommend "HERE" is necessarily in-line with actual early B707 TYPE operating procedures, but rather, it represents how I've, personally, learned to fly these simulations over the past 6 years .... and to best advantage I feel !
For starters .... ensure that your B707 simulation is within it's certified MGTOW (257,000 LBS for the B707-120). I do this by simply adjusting my fuel loading as follows ....
LEFT AUX = 87%
LEFT = 80%
CENTER = 67.8 %
RIGHT = 80%
RIGHT AUX = 87%
CENTER 2 = 100%
Doing this should then result in a 44 LB (only) overload .... and which will be burned of during taxiing anyway.
Whether or not the above fuel load configuration is an authentic B707 TYPE loading .... "I know not"
What I've stated above is simply "CONVENIENT". Within FS the actual fuel configuration hardly matters anyway. So long as the simulation isn't excessively overloaded or unevenly loaded .... is all that really matters.
With the B707-120/138 (P&W JT3C-6 turbojet powered versions only) .... maximum thrust (N1 100%) should always be set for T/O .... literally fire walling the power levers was normal with these particular aircraft. The same applies also to the B367-80 and the military C135-A SERIES aircraft too. Flying the remainder of the B707 series .... T/O power should not ever be set in excess of the pre-bugged engine guage settings which visible in each of the panel versions. These pre-bugged settings represent the maximum allowed/recommended engine power settings for each of the simulated aircraft version engine types under most comon operating conditions. Using the correct panel version with each B707 TYPE aircraft is therefore absolutely essential in order to be able fly these simulations according to the recommended numbers ... and to realize the correct aircraft/panel performances. Ensure you're using the B707-120 1959 panel (only) with your B707-120 simulation !
Up to 30* (degrees) of T/O flap can be used for B707-120/138 aircraft .... believe it or not. If heavy use FLAP 30 .... and if light FLAP 20 will be more than sufficient. T/O will still be long a very long run regardless .... possibly exceeding 3/4 of the length of the longest KSEA RWY (34R/16L).
Line up with the centerline at the RWY threshold.
Lock the brakes "ON".
Apply maximum thrust .... and then activate each of the 4 WATER INJECTION switches (B367-80 and B707-120/138/C135-A SERIES aircraft/panels only). These boost engine thrust by roughly an additional 10%.
When all 4 WI lights illuminate (approximately 20-25 seconds later) .... release the brakes and roll for T/O .... rotating at the pre-calculated T/O VR speed. AT MGTOW the following T/O V-speeds should apply ....
V1 = 135
VR = 146
V2 = 159
V-REF = 169
Select the gear up as soon as a positive ROC (more than 500 FPM) is indicated per the VSI gauge.
Set a roughly 1000 FPM initial ROC.
Retract the flaps to 20* at approximately 200 KIAS.
Retract the flaps fully at approximately 220 KIAS .... failure to do so will trigger the config alarm !
Select the YAW DAMPER switch to "ON" .... and then increase the pitch attitude to achieve whatever climb rate is necessary in order to maintain a 270-290 KT climb speed .... and which should result in a roughly 1500-2000 FPM ROC .... reducing later with altitude.
Activate the AP .... and then use the vert speed thumb wheel to trim the simulation/set the climb rate .... which does makes life a lot easier.
This's also where things start to get a little more difficult too .... for the "NEWBIES"....After T/O and cleanup .... engine power should be adjusted to whatever thrust setting is necessary to maintain a climb speed of around 270-290 KIAS .... whilst also trying to ensure that N1 engine power indications don't exceed the N2 values. Ensuring at least 1-2% difference between both N1 and N2 values is my own personal goal, but, doing also results in a lower power setting which then imposes a much more shallow climb rate .... 1000 FPM and reducing further with altitude .... to as little as 500 FPM .... and which, if the simulation is heavy to start with, makes for a "VERY LONG CLIMB TO ALTITUDE".
FL310 is my usual target cruising altitude, but which .... beyond FL200 .... requires a constant step climb procedure with level-offs at around every 1000 FT of altitude in order to gather speed .... then climbing again at around 500 FPM in order to eventually get all the way up to FL310 .... whilst also trying to maintain a 270-290 KT climb speed throughought the climb as well. Not easy, but, is "IS" workable !
If greater speed for still good engine indications is evident .... then the ROC may be increased slightly.
In level cruise at FL250 performance indications should be as follows ....
EPR = 2.17
N1 = 88.2%
EGT = 501
N2 = 89.7%
F/F = 3135 LBS PER HR (per engine)
IAS = 351 KIAS
MACH = 80.6
In level cruise at FL310 performance indications should be as follows ....
EPR = 2.25
N1 = 86.9%
EGT = 463
N2 = 87.9%
F/F = 2477 LBS PER HR (per engine)
IAS = 304 KIAS
MACH = 79.7
The above observations are what I've just recorded "today".
Some of the indications appearing within my B707 Handling Notes have not been updated "for a very long time". There have been any number of refinements to these B707 aircraft panel/guage/FDE sets since that information was first posted here. It's one of those things I'll update .... when I've time to do so since it's an extremely time consuming exercise.
As mentioned above .... the B707-120/138 simulations aren't easy to fly well without practice !
Speed and engine indications during the climb to altitude must each be constantly monitored .... and the simulations attitude then adjusted accordingly. Skill, concentration, and good planning/judgement are absolutely essential in order to be able to fly these simulations well
Mark C
AKL/NZ
All of this is assuming you are using real weather.
What I've stated above is simply "CONVENIENT". Within FS the actual fuel configuration hardly matters anyway. So long as the simulation isn't excessively overloaded or unevenly loaded .... is all that really matters.